Spy party - split into two teams or not

[3bunnies]

Somehow the guest list has escalated. We now have 14 9yr old trainee spys due to decend. Part of their party is a mission (treasure hunt) with complex clues. I can't decide whether to split into two groups and set them off solving two halves of the same mystery or set up loads of different threads in the hope that they will divide up naturally or whether to just let them all charge around our tiny 3 bed house in one big team. I am planning the treasure hunt myself so the last one would be easier but not sure which would work best.

I think either it is one group or you need to split them evenly. 9 yo DS was at a laser quest party where the teams weren't in balance and he was incredibly upset behaving like a spoilt brat demanding to go home

I think maybe I should split them but it is hard to know how to do it. There are two who I think will find it harder so I might split them into different teams but not sure whether to plan who goes into which team or do it randomly. I would like ds (4) to be with one of his sisters but then dd immediately started figuring out who were her closer friends and who she would definitely want in her team. I wasn't keen as an adult it seems unfair but although they do all play together at school there are a few subgroups and maybe they would be happier with their best friends too. I am not planning to pitch them against each other and will encourage collaboration.