hey todd
like david has mentioned, this subject has been posted many times here. you can do a search, middle of page with magnifying glass with answers there. the city has cracked down on illegal apartments as some other cities in this world has done. lots of travelers have loved their experiences but on the other side, residents have hated it and despised how people have invaded the area near or at their home. been in the newspapers all over. what feels good on one foot does not fit well on another foot. they want to live like a local, some locals can't be bothered. some places have restrictions on how many people in a hotel room/apartment double is 2 triple is 3, if you exceed that they can have you removed, plan and simple, airbnb, vrbo, etc needs to have 13 number registraion or it's illegal. it's that country's laws and rules, we need to follow. check booking.com, put in filters on left side and shows what's available, trip advisor.com same thing about filters.. try priceline, expedia, and see if there is a place for all 7 of you or hotel with 3 rooms near each other. check bedrooms, how many bathrooms, beds and what type (twin or double), deposit, what area. remember rooms are smaller in europe. good luck
aloha