RoboHelp 7 alone should handle this. There is nothing
RoboHelp Server would do that would help.
If you are deploying a product that is installed to the
desktop, you would simply include the help for the modules that are
installed. You probably have a person responsible for the installer
if this is the case. You would alert them that only the help for
purchased modules needs to be installed.
On the other hand, let's say your product is server based. If
this is the case, you will need to restrict access to the help
based on the user's login. Assuming this is the case, your
developers have already sorted how to restrict access based on some
criteria. They would use the same criteria to restrict access to
the help as well.