1. Where people have had good times?
2. Surf schools that can cope with up to 20 begginers in that area?
3. What amazing accomodation have people stayed at?
if your looking for fun, definately head to lagos in the algarve, they have plenty of bars, restaurants, cool beach spots and most of the surf schools can accomodate large groups, but usually will split you up in smaller groups of 6 to get to the surf spots as most places use 4x4s to get you there.
unfortunately the company i stayed with went bust a year ago, but there are lots of other schools around.
also, baleal surf camp in peniche was amazing, they definately have space for 20 people, they have a surf house with hostel type accom and apartments if you want something more luxurious.
all the accom is within 5-10 min walk from the beach and the surf school and was clean, comfortable and great for the price, but the best was the instructors, i did the advanced course and had a blast with all the guides, who really made you feel at home.
hope that helps!