Hi,
I'm afraid this is not possible, this restriction is imposed by Windows Installer. You cannot include the same merge module multiple times into an MSI package.
The solution is to add this merge module into a separate feature, which does not contain other resources and set this feature as hidden, and not installed by default.
The write your own script,
following our example, to control the install state of the feature, based on the install state of other features from your package.
Regards,
Bogdan