She should still be praying separately as the men are non-mahram. Unless, they have proper facilities like a mosque/prayer hall where this is a special secluded area for the sisters.
Women are not obligated to pray in congregation by the way. It is better if they pray it on their own, rather than join jamaat of non-mahram men, where they don't have a place of their own (secluded area) to worship in peace.
thanks for the clarification. i was pretty sure it wasnt permissible. i know prayer in congregation isnt fard for women, and just wanted clarification on this issue.