The docs don't have a great example of it, but you can override all of the CRUD operations for models, including creation. You can handle creating and saving the model yourself, at which you have the primary key, and can make any other queries and create any other models you need.
I cobbled this together out of our code, so hopefully it's complete enough. Let me know if any of it's confusing, or it doesn't answer your question.
http://flask-admin.readthedocs.org/en/latest/quickstart/#model-views
from your_models import Employee, Manatee
from flask.ext.admin import Admin
from flask.ext.admin.contrib.sqla import ModelView
class EmployeeAdminView(ModelView):
# this is called when a model is created
def create_model(self, form):
person = Employee() # create new Employee
form.populate_obj(person) # use WTForms to populate the model
# create a new manatee for this new employee
# everybody needs a manatee for business purposes
# this assumes there's a sqlalchemy relationship() between the two models
manatee = Manatee()
manatee.name = "Janet"
person.manatee = manatee
self.session.add(person)
self.session.commit()
# at this point person.id should be available, so you can use that here
# to make any other queries you need to
return True
admin = Admin(app)
admin.add_view(EmployeeAdminView(Employee, db.session))
