Must women wear the hijab during preaching circles among themselves on the pretext of the presence of angels who are ashamed to look at them unveiled?

There is no explicit, authentic text indicating that angels do not attend gatherings where a woman unveils her hair. This has not been mentioned among the known impediments to angels entering, such as the presence of a dog or a picture. It has been reported that Gabriel used to descend with revelation upon the Prophet, peace and blessings be upon him, while he was in a single blanket with Aisha, and it is known that a woman would not be in her complete hijab while in her blanket. The hadiths that might be cited as evidence for this are weak and inauthentic, or not explicit in this regard.