I think Gamma and Delta quadra members are most susceptible to acting in a nepotist way, due to their Fi, which means they have an attachment to the people they know and like, rather than to rules and regulations. Alphas and Betas are more likely to abide by the rules and tell one of their friends to fuck off if they're trying to secure a place in office or something.
I think this is more relevant to Se/Ni quadra members, since they're the kinds of people who strive to achieve and gain entry into the higher echelons of society. Nonetheless, Deltas and Alphas might play some part at least in this.