Women only locations?
A colleague of mine in our theatre club wrote a successful short play involving a bride-to-be, her mother, and her grandmother. The bride-to-be was having second thoughts on the eve of her wedding, and was trying to hitch-hike dressed in her bridal gown.
A nunnery. But why not have some of your female actors play male roles? It's hardly revolutionary ...
Why not put them in a Twilight Zone situation, a void, for example, because of something in their character/personality that caused hurt, harm or distress to someone else or because they need to face an issue, crisis, or something.
A hairdresser's, a hen party, a 'pamper party' where young teenagers are having hair and makeup done, an ante-natal class...a group of bridesmaids waiting for the cars to pick them up to take them to the wedding...
The medical office I go to is all women, from the receptionist to my doctor. No men work there
Depending on what country you are in, the Women's Institute, the Country Women's Association, View Clubs are possibilities.
Well, er, "eva", at least you "already have" two. Something to be proud of. And they're really fantastic ones too. Prison and boarding school. Really impressive. You know, I bet you're far more intelligent than you sound.