Hello, someone has two females and one male together? No problem with the females?

Your question is not clear.
If the male is not neutered the females will get pregnant.

I mean if females fight or babies are stolen or killed

There are many problems that can arise from having 2 Females in the same cage as one male… Firstly, are the females related? Is the male neutered? (Im guessing not) if he isn’t you need to be prepared for rejection/cannibalization… Some females will pull their joeys, cannibalize the other female’s joeys, or even snatch the other joey and fight over it… It would be best to neuter male if you don’t want joeys… if you do then I would highly suggest that you only have one female and male together... Trio’s (2 girls and 1 boy) work best if you have twin sisters… There will ALWAYS be a risk with trios the same with there is ALWAYS risks with breeding! Be prepared for the worst just in case…. Do you have lineage on your gliders to know that they are not related to prevent inbreeding?

*I apologize if you cannot understand this*