Set course-specific developer variables?

I understand how user/learner variables work, but what if I want to easily establish some variables on the developer end that are specific to each course?

For example, say I want button tied to a link (URL) to a course discussion forum specific to the course in question. What I'd like to do is have a spot on a hidden first slide where the developer can paste that URL before publishing. The forum button then addresses that specific URL in the published course, taking the learner to the appropriate discussion forum. So I'm not using a text entry field. I just want to define a variable on-screen without the developer having to take extra steps setting it up. They would just have to paste the URL in the appropriate spot on the slide. Is this possible and how would I make it work?