Is it permissible to sit in a gathering where men and women who are not mahram (relatives one may not marry) are mixed together?

Question:
Honorable Shaykh, may Allah grant you success. A questioner says: If it is the custom of my family that women sit with men who are not their mahram, is it permissible for me to sit with them?

Answer:
If the women are mixed with the men, then it is not permissible. However, if the women are separate and the men are separate, there is nothing wrong with that, provided the women cover themselves and observe the hijab.