Bootstrapper: Check if msi version is installed before running

Question

I'm trying to find a solution for the following issue:

I have numerous programs (lets call them slaves) that all rely on a single program (master). I need to distribute an installer for each slave. This installer needs to install the master.

I want to be able to version both pieces, so multiple msi's appear to be the right solution, chained with a bootstrapper.

My problem is if a slave installer installs the same version of the master that is already installed, the .msi will run in repair/remove mode.

This is unacceptable from a user standpoint and will just cause confusion.

Is there any way to check for a version of the currently installed fiels before trying to run the msi?

I am currently using WIX's setupbld.exe as a bootstrapper.

Any other solutions greatly appreciated (I have also tried merge modules with no success, since the versioning is useless)