If many women gather, whether in a rest area, in the desert, or at an event,

at family gatherings, is it better for the prayer to be performed in congregation or for each woman to pray individually?

Both are permissible, it is allowed for women to pray.

Separately, and it is also allowed for them to gather behind one of them who leads them in prayer, or for her to stand in their row. Both are permissible, yes.