Spend time with all of them, and I mean all of them. Ask them all (Seperately, of course) just to go out on a date. (You know, just for the fun of it ^^)
If you feel your heart pounding and your palm getting sweaty and everything on any of them, dont go straight into the relationship. 'Date' the other guys, too. I mean, if you arent 'going out' it isnt cheating.
Now Carlos, on the other hand, from the 'shared' thing, I really really dont like him. Selfish child is what he is, and all he's ever gonna be till he's in his 60s. Thats how alot of men are. (Not all, just a few I know.)