Basic MSI project as both basic install and merge module

[liberybell]

I have a basic MSI project that installs my client application, which I call project A here.
I have also another basic MSI project that requires my client application to be already in place (called here project B.)
Is there any way I can use project A as a merge module of project B so I don't have to manually verify if project A is already installed?

[KathyMorey]

That depends.

Do you want product A to show in Add/Remove Programs regardless of how it's installed?

Do you need product B to show in Add/Remove Programs? Have you considered making product B a conditional feature in project A?