It might be worth cooling off your friendship with them for a bit, don't bother trying to be friends with the 'group' if they are ***** to you. On the other hand don't reject all of them on the basis of them being part of the group, if there are some lads who are your genuine friends amongst them then its worthing sticking by them.
I was in a pretty similar situation to you in year 11 and it gets loads better in Sixth Form (sorry if that feels like a long way away). The stupid ***** leave and become irrelevant, the slightly more intelligent people are forced to show you some respect because they realise that the people who are academically successful are going somewhere.
Don't worry about your repuation, no one will care once they get to know you. The drinking thing... may just have to end up conforming but don't become one of those
'i had four pints of strongbow, eight shots vod, and a pineapple bacardi breezer and i was paraletic mate' Nobody really likes those people.