Let's be honest; if everyone's silent and you start talking to the hot girl, everyone will know what is up. So you have to work around it.
Get the group talking. Ask someone for something, preferably a guy, in a nice, friendly manner. It can be literally anything; "Did you take notes last time?" "I heard we're having a test today, is it true?" "*some random biology-related question*"
The person will start talking. He/she WILL. Continue the conversation and someone will eventually catch up. Maybe try couple of times. If it goes nowhere, I feel sorry for you and the group of f***tards you've been assigned to. Then there is nothing to do, try opening the hot chick directly and maybe you'll have some success.
But, for the sake of normal life, let's say that the conversation starts up. BOOM. You have just made a new social circle. By definition, you're an alpha-male (warning: don't do it from the position of "must make them start talk," instead take it as "let's give these people opportunity to express themselves as they want to") of the group and the blonde should fall right into your lap.
Or at least become receptive to your advances.
Anyways, have fun tomorrow
