Python-сообщество

class Field(models.Model):
    ...
    for_personal = models.BooleanField(u'Только для персонала',default=False)
  
class Answer(models.Model):
    user = models.ForeignKey(UserAnswer)
    field = models.ForeignKey(Field)#,limit_choices_to={'for_personal':True,},)
    data = models.TextField(u'Текст')

class UserAnswer(models.Model):
    ...

class AnswerInline(admin.TabularInline):
    model=Answer
    extra=1
    radio_fields = {"field": admin.VERTICAL}
    
class UserAnswerAdmin(admin.ModelAdmin):
    ...
    inlines = [AnswerInline]

admin.site.register(UserAnswer,UserAnswerAdmin)