Following a question from @Mauwiks... natively in WHMCS, there is no way to do this - but with the help of the attached hook, it is possible - just upload the hook to /includes/hooks the hook currently includes EIGHT different parameter options - I can think of at least 4 more options that I could add, and may do so at a later date, but I think 8 is plenty to be going on with. 🙂 note: the addon's ID value can be found when in the URL when you edit that product addon in the