What does one call a group of similar courses where only one can be taken for credit?

A couple of universities that I've worked and/or studied that described the courses as having equivalent content. So, the prerequisites for an upper-level course might be listed as "MATH 344 or equivalent content."

The reverse descriptor also came up sometimes. For example, the degree requirements for a given major might include: "Four additional courses at the 500 level, of essentially different content." Another school used inequivalent content for the same thing.

I think anti-requisites might be a good choice, since it would fit with other necessary concepts in the context (pre-requisites and co-requisites). Moreover, it seems to me to have a reasonably intuitive meaning even if it isn't the word you normally use (in this context it is very important that words are not misinterpreted).

A quick search suggests it is used by at least some universities, e.g. Western University:

Antirequisites are courses that overlap sufficiently in course content that both cannot be taken for credit.

My university has a concept of some courses being "incompatible" with other courses. See for instance: this course listing.