What is the phenomenon in young females and their groups called? I thought it was being a groupie I was wrong:?

this specific phenomenon where girls with individual personalities while alone, turn into completely different people while with there friends or larger female dominant groups , almost like they turn into an unconscious chorus of spontaneous cataclysmic social reactions to their external environment and events within.
This happened after a girl I met at the start of the year at university was the most beautiful women I have ever met, and then we decided to spend our holidays to ourselves but on returning I can barely talk to her, I managed to squeeze on conversation away from her friends somehow under their permission for a limited time??? But it was like her usual self and she was still nice, but ever since then when I try talk to her with her friends it's clearly going nowhere, it's uncomfortable awkward and from what I know believe they are like actively trying to counteract our interactions and she just don't seem to have a voice to stand up.

Thank you to anyone who gives me there time of day to try help me understand, this is very confusing and distressing to me and generally speaking has my mind at a sort of hold, but I really don't get how to describe what is happening but it would really help and I hope this is the right place to ask- thank u