Q: Ilm-39: Four brothers and their parents live in a house and because it is small, it is nor possible to allocate separate quarters for them all. Furthermore, some works, some are not working, others are studying and often they all need to enter at the same time. How is it now possible to observe purdah? Will it be permissible to exclude the face, hands and feet? If it is permissible, the problem is that evil thoughts develop when seeing the face and if not permissible, how must domestic activities take place? Wives of different brothers are often seen by the other brothers. (Abridged)

Answer: In such circumstances. the women have to exercise extra caution and as far as possible, they must not have their faces exposed. If they sometimes appear before another husband out of necessity, there is hope of being forgiver-r if the heart is clean.
And Allaah knows best what is most correct.

Fatawa Rahimiyyah vol.1