Product A with its own setup (very similar to

Product B with its own setup (very similar to A).
My task is to create new Product ABC which contains the existing products A and B, and a new product C (similar to A and

My way: I take the setup of Product A (re-use) and enhance it with B and C. Product-Code, Package-Code and Upgrade-Code of Product ABC are different to Product A !!!
The problem: If Product A is already installed the dialogs of the A setup appear after the start of the ABC setup!!! If Product B is already installed the correct dialogs of the ABC setup appear after the start of the ABC setup.
My analysis by now: very early (before any action) the log-file contains the following line
MSI © (30

I think the problem starts here. Why does the setup look for a appcompat database entry for Product A if the setup of Product ABC is started?

Please help!