Definitely I would do this room sorting before you actually go there. That way you know how things will be when you arrive and it does not cause upsets when you get there. If you are staying perhaps for a fortnight you could also agree whether you might exchange rooms to have a fair share of things. Or possible offsets might be who then gets most comfortable seating in the lounge or in cars if you are going anywhere. You do not say whether these are already friends or perhaps a group who get together for a specific interest. If you dont usually see each other a great deal, it might be a good idea to discuss other things , for example, what sort of time are you going to eat a main meal together, as this can be very varied in everyday life and what time you might decide, is time to be at least more quiet in the evening so possibly agree not to play loud music after 11pm. Sounds a bit bossy or restrictive but if asked about in advance you might be surprised by the variety of peoples "normal" things. Easier to deal with in advance rather than spoil a time when you are there.