Is there any way two adult female mice that don't know each other can get along if they are in the same cage?
Yes, female mices can get along once they get used to each
other. Introduce the mice outside the cage first and see how they
get on. If they don't fight try this: clean the cage you are going
to put them in very well (to get all the 'mouse' smell off it) and
then put the female mice in the cage together at the same time. As
this cage has been cleaned it should be neutral territory and
therefore the female mice should not fight. If they do fight you
might want to consider houseing them in different cages.