Okay. Then I would recommend the following deployment scenario:
1. Compile your "Helper" tool with an unique Product GUID. I would suggest to create a silent install or launch it in silent mode at runtime.
2. Add the "Helper" tool executable to your main project(s). See attached screenshots. The code checks if the Helper Product GUID exists. If this is not the case, it "installs" the Helper.exe installer into the temporary Windows folder and launches it. Then it deletes the file.
This will install the Helper tool.
Does this help?
Friedrich
P.S. If you also need some tips on how to uninstall it from your main products, let me know.