If the woman is abroad, she should have a Mahram.
A woman cannot be a Mahram for another woman; nor can a mother be a Mahram for her daughters. If she is with her daughters, or other women in a detached house or apartment, it is not necessary to have a male Mahram with them. However, if the house or apartment is insecure because of the ill-behavior of the neighbors, they must move to another house or apartment in a secure neighborhood where they can avoid Fitnah (temptation) (Part No. 17; Page No. 342) or violation of prohibitions. May Allah grant us success. May peace and blessings be upon our Prophet, his family and Companions.