It sounds like there is a more general issue here. That is, it would be helpful if there were some general mechanism for systemd files could behave differently, based on the content of /etc/sysconfig files (maybe there is but I just don't know it). For example, systemd unit files support ConditionPathExists=, ConditionKernelCommandLine=, etc. Maybe we need to add some new unit file directive(s) like ConditionPathContainsMatchingLine= or something...?