qt/pyqt how to share data between two models

Question

Suppose, that you're writing an office application for accounting. Your customer is a bakery, it employs a set of bakers, who cook pies.

You make 2 spreadsheets:

1. First one presents a table (bakers x days), where each cell contains the number of pies, cooked by each baker each day.
2. Second one is (bakers x data), it presents personal data of bakers, such as salary, telephone number etc.

Each spreadsheet corresponds to a custom QTableModel and QTableView.

Now, I want to present an API to the customer, so that he can programmatically change his data. I want my program to have a console; through it user will be able to modify the storage of bakers' data, called Bakers, which both models use to draw data from.

To add a new baker to Bakers, user should call Bakers.add(); I'd like it to traverse all models and call insertRow() method of each of them.

But here comes the problem: in insertRow() implementation you should call beginInsertRow(), then actually add new baker to Bakers and then call endInsertRow. That way I'll end up having a baker inserted twice, cause insertRow()should be called for each model. Could you suggest a way to circumvent this problem?