the OP states that its some girl that (he thinks) likes him, they are not together, not on a date, havnt dated before etc etc
its not his bird

I dont think anyone with real respect for you would purposely try to make you jeleous - unless they were about 18

so as long as you have respect and value for yourself, you will know what to do

maybe she is just chatting to them like normal people do, and its in your head and your own insecurity thinking she is trying to make you jeleous.

my ex (stunner looked like cheryl cole)
would purposely not chat to guys, to the point i would notice akward situations happen -- ie stood in a que, someone behind her would say hello to her and there would be akward silences
- i said to her-- that was random what was that about -- she said it was her ex
i just laughed- called her a nob and said you should have just chatted to him i (genuinely) wasnt bothered
or she would get a drink from the bar and some guy would talk to her who has swapped eye contact with her before - i asked who it was when she came back
she said he said to her he didnt want to come over as i looked like i would kill him
again i said im really not bothered
im really not-- whats the harm in that, i would only be bothered if i felt insecure about our relationship or she was actually doing somthing that i would be truly bothered about - im no fool