from django.db import models

class parent(models.Model):
	name = models.CharField()

class childA(models.Model):
	parent = models.ForeignKey(parent)
	some_field = models.CharField()

class childB(models.Model):
	parent = models.ForeignKey(parent)
	some_other_field = models.CharField()
	some_field = models.ForeignKey(childA, limit_choices_to={'parent': 'parent.name'}) #This will make a select box for some_field values where childA.parent == 'parent.name'.  Is there a way to have it limit to childB.parent.__str__ (dynamic based on parent value selected)?