Is it possible to have unprotected sex with 2 different persons that are hiv+ and not get infected yourself?

Yes but not wise: Hiv does not automatically happen whenever there is sexual contact. Much depends on which partner is hiv+, viral load, open sores or cuts, presence or absence of ejaculation, etc. However, it is very unwise to risk contracting HIV with such risky behavior. A life-long illness for a momentary fling is not worth it.

It is possible: Just like playing russian roulette , it is possible that you won't get shot in the head with two clicks, but why would you want to play this game?