I’m not exactly sure if I understand well. Nevertheless, simultaneous model merge/update is possible - in the Convertor dialog. You have to change the settings to meet your needs - select the appropriate icons for Model1 and Model2 to merge to existing model or a new model, and to define which changes you like to apply and in which model (defining the blue arrows).
Please find attached a simple example where I’m trying to show what to do, how to make the changes etc.
Please feel free to play with the Convertor, OTPs, blue arrows etc. and ask us if you need any help.
Flash movie on the Convertor is available at:
Example_Simultaneous_Model_Merge.pdf (354 KB)