Specify conflicts for packages with CPack

I’m using CPack to generate packages. Some of these packages conflict with eachother, so only one of them can be installed at the same time. Since I’m generating debian packages, they support storing this information inside the package, but I’m having a hard time figuring out how to get CPack to add this option into the package.

What variable should I set to mark the package as conflicting with another package?

Have a look at CPack Deb specific variables, in this case:
CPACK_DEBIAN_PACKAGE_CONFLICTS

Well that’s embarrassing, I completely missed there was a separate page for debian-specific options. That is exactly what I need. Thanks!