Help With Friends in middle school?

I just went into middle school and ALL of my friends are guys,my best friend,tyler, hangs out with this seventh grader.he only wants to talk to tyler.so we(me & my other friends)can't talk to him,if we do the 7th grader gets pissy.its breaking us apart.my best friend gets excited when he leaves & starts talking to us.also, my friends won't hang out with me anywhere x-cept for @ school cause i'm a girl.any tips?