Thanks for the responses, gents!
I have a fair bit of experience organizing parties with 3 or 4 GPs in Europe, the US, and Colombia, at my hotel or Air BnB. Usually going about 3 hours, sometimes longer. Generally they have been super hot, sometimes just off the charts spectacular. Occasionally a guy will be a dud and just isn't into it, or doesn't have chemistry with the other guys, in which case I diplomatically send that boy home after the first hour. In such cases I will usually have fun with the other guys deciding which new GP to invite to sub-in (so to speak.) My goal is usually to mix things up in terms of roles and body types.
The problems I have had are not related to jealousy or anything like that, but more generally if a guy shows up who has already been partying and is strung out - although that has been infrequent. And usually I find that the boys police themselves. If one of them is acting strange (e.g. is strung out) the other guys will tell him to leave, etc, and are very protective of me as their client. As far as I can recall, the guys have all gotten along. In fact I hosted a party with three scorts in Phoenix this year and found out that two of the guys who met at my party hooked up as partners, and started travelling / living together, LOL! (Never expected to be a matchmaker!)
I think the key to my successful experience as a party host has been:
1) to focus on guys with profiles with obvious tells like "long sessions," "threesomes and groups," "parties / gusto fiestas / fiestero" etc;
2) to avoid guys who I think are probably straight / gay for pay;
3) to be upfront with the guys on what I'm planning and looking for.
4) just to be generous / friendly / reliable as a client.
In my experience, the kind of group sessions I put together are their ideal work session. They get multiple hours in, they have other hot young guys to play with, and they probably feel safer from potential client exploitation if they have friends / peers involved.
My proposal above was to see if anyone else out there wanted to join forces in a session like this, with say me sponsoring the sort of party I normally would do solo, and another client / other clients joining in and sponsoring more lads. Let's call it a GP pot luck! it could get complicated, but if everyone is chill and has fun it could be amazing.
I'm not sure why this would be more difficult in Brazil than it has been for me in other countries (although I'm a little more concerned about the security aspect.) Obviously moving this many guys in and out of a hotel is a non starter, and very difficult at most Air BnBs (that can be strict about admissions.) So I was thinking of experimenting with this by renting a suite at the Hotel Chili in SP for a few hours, and welcoming the guys there (where they would have to give their ID on the way in, etc.)