I actually have a similar situation in my nursing program - a clique that is high profile (one girl is a student rep), and they suck up to instructors yet treat some of their classmates rudely (myself included). Sometimes it seems they are more interested in "passing the boards" than learning the material. Two of them are inseparable to the point that I wonder if either could function in a nursing position alone. One was taking anti-anxiety meds early on the program.
I have distanced myself from them and maintain a polite, cordial and completely professional stance with them. If I need to deal with them, I do it pleasantly. I will not be dragged down to their level. I am all about personal dignity lately. Many of my classmates seem to distance themselves as well.
They have a "study group", where they meet at one's house with bagels and such - I'm doubting much studying is getting done since I know what they got on some of their assignments last semester. I myself have a 4.0 average.
is temporary, so I ignore as best I can and stick with the nice folks - I know I will do well. However, if it's that toxic at your job, I'd find a new position elsewhere, you can spend a lot of time and energy fighting it but you have to consider your own personal well-being.