Well, one of the most prominent signs is, are they trying to isolate you from your friends and family?
Cults gain members by starting open and friendly, and reinforcing a person’s self-perception that there is something wrong with them or their life, and then offering vague “solutions” that they can provide. Once you start accepting this “assistance,” they begin isolating you from anyone who could help you realize you’re in a cult; primarily your friends and family.
What about this group makes you think it may be a cult?