Bidirectionnal mirroring

Hi ! (sorry for my bad english)

I’m trying to configure mirrors between gitlab repos but I saw that bidirectionnal mirroring could result in conflicts.

What i want to implement is 2 “push mirrors”, if I modifiy one project, it pushes onto the other, and vice-versa. Do i need to implement “pull mirors” ? Why can 2 push mirrors be enough ?