Trading from Mexico

Hi!
I want to save time and headaches studying for a situation in Mexico.
I traded for several years and now we are going to start a fund with several friends.
It’s as simple as a responsive letter but when you’re trading leveraged it’s hard to justify with a former friend.
There is series III and the concept of margin and “The money in the fund” which makes the situation risky. It seems that the solution in Mexico is via trust, agreements, etc. There is no legal figure. The ideal would be series III and formulate an armored agreement that avoids risks.
I use Bloomberg terminal the interface is simple, the rules are easy to understand, similar to my current RT provider
“Associate” I think that is the term here. But whoever hits the button is jointly and liable risk.
Greetings