Asmall group of friends that will ignore others, focusing only on themselves, is known as a

A small group of friends that will ignore others, focusing only on themselves, is known as a clique. 

I believe this is defining a clique. A clique is a group of people (generally friends) that will not acknowledge others and will sometimes be mean to others to try to display their dominance. This can be traced back to the original humans where human instinct made those who brought back the most food the "clique" whereas those who did not do well were bullied by the "clique."