Manupular admin forms in Django

I am using inline in an admin admin in django, I create 4 forms

def get_min_num(self, request, obj=None, **kwargs):
    return 4

def get_max_num (self, request, obj = None, ** kwargs):     return 4

However, I have a field that I need to have a different predefined value in each form. I do not know how I could manipulate the "iteration" of the form in order to make the change in each of these, nor what function to use.