Somebody has to organise it. The three-generation family trip, the big anniversary, the golf week that grew: someone says, "We should all go away together," and everyone agrees enthusiastically. Then the work lands on one pair of shoulders. This guide is for that person. Organising 15 to 25 people is a different job from booking a family holiday. Still, it breaks down into a handful of decisions, and if you take them in the right order, it is genuinely manageable.

1. Start with the sleeping plan, not the dates

The first question isn't "when can everyone do"; it is "where does everyone sleep?" Groups fall apart on bedrooms: who gets the good room, which couple ends up on a sofa bed, whether the teenagers are sharing with the toddlers. Solve it before you fall in love with a villa. Count your couples, your singles and your children, then look for two things: en-suite bathrooms (one shared bathroom per five adults is how friendships end) and twin beds that push together. Twins that convert to doubles are the organiser's secret weapon, because the same ten rooms can sleep ten couples this year and a golf eight plus grandparents next year. As a worked example, Villa Lux Luz in Praia da Luz sleeps 20 across ten twin en-suite bedrooms exactly this way, and can add hotel beds (€150 per stay each) and children's Z beds (€75) for up to 30 in total. Whatever villa you choose, get the room list in writing and allocate rooms before anyone travels, not in the driveway.

2. Collect the money before you book, not after

The organiser's classic mistake is paying a deposit on a promise of "we're definitely in" and then chasing transfers for months. Do it the other way round: agree on a per-head figure and collect it into one pot first, then book. A shared banking pot or a simple spreadsheet both work; what matters is that the money moves before you commit on your card. Two practical notes. Most villa bookings carry a refundable breakage deposit (€1,000 is typical at this size) paid with the balance; decide up front that it is shared equally, and say so. And build a small float, five per cent or so, for the things nobody thinks of: pool heating, extra beds, the last-night dinner.

3. A realistic per-head budget

Big villas look expensive until you divide by twenty. Working from the published guide rates for a 20-person villa in Praia da Luz: a winter week from around €3,500 is €175 a head for seven nights; the May, June and September shoulder at €5,000 to €7,000 works out at €250 to €350; even peak August at up to €14,000 is €700 a head, which is what a mid-range hotel would charge one person for a fraction of the space and none of the privacy. Flights, food and the fun budget come on top, but accommodation, the number that frightens people, is usually the pleasant surprise.

4. Moving 20 people from the airport

Don't try to book five app cars from Faro at midnight. For a group this size, the answer is pre-booked minibuses, one or two vehicles sized to your party, booked with your flight numbers so a delay does not strand you. Expect from around €190 per vehicle for the group run to Luz or Lagos. The options, costs and caveats are all in our Faro Airport transfers guide; whether you also want to hire cars for day trips has its own guide.

5. Feeding a crowd without one person cooking for twenty

The meals are where big-group holidays are won. The pattern that works: a stocked fridge for breakfasts, lunches that sort themselves around the pool, and then a mix of three things for dinners. Book a private chef for two or three nights (especially the arrival dinner, when nobody wants to shop), eat out on the others at restaurants that genuinely take big tables if you warn them, and keep one barbecue night for the group's self-appointed grill chief. Book the chef nights and the big-table restaurants weeks ahead, not on the day.

Staying in a villa near Luz? We can arrange all of this for you, from chefs and fridge stocking to transfers and boat days: marktheconcierge.com.

6. What to book months ahead, and what to leave

• Months ahead: the villa itself (summer weeks at big villas sell out first; high season usually runs Saturday to Saturday with a seven-night minimum), flights for the group, airport transfers, chef nights, and hire cars if you travel in summer.
• A few weeks ahead: boat trips and dolphin watching, big-table dinner reservations, pool heating if your dates are outside high summer.
• Leave until you arrive: beach days, the market, which bar becomes "yours". Overplanned group holidays are worse than underplanned ones.

If your group can travel between November and March, one more organiser's cheat: changeover days loosen up outside high season, so you are not locked to Saturdays, and winter rates make the per-head numbers almost silly.

7. Plan for the group to come apart

The best big-group weeks are not twenty people doing everything together; they are twenty people under one roof doing three or four things in loose formation, then reconvening for dinner. Look for a villa with enough separate spaces that the early risers, the nappers and the card school never compete for the same sofa. One guest, after two August weeks with 24 people across three generations, put it exactly: "Finding somewhere that works so well for 24 people, across three generations, is no easy task, but this villa gave us everything we could have wished for." That, in one sentence, is the brief.

Ready to look at dates? Villa Lux Luz sleeps 20, up to 30 on request, a short stroll above the beach at Praia da Luz.