I found that Multiple Mario Games have subcategories for relays ( https://www.speedrun.com/multimario?h=3D_Mario_1862-Relay&x=02qlyopk-0nwpy2x8.zqoe4z5l ), and I wonder if you could add a relay subcategory under Main Series Glitchless.

Most rules are the same as Novecta (Gen 1-8 incl BW2) (JP). Additional ones for relays are the following:

1. You must have at least two people on a team to submit a run.
2. Games must be run one at a time. A runner can start the next game as soon as the timing of the previous game has ended.
3. Timing ends once the last runner finishes their category.

The following playlist has our runs: https://www.youtube.com/playlist?list=PLBaIQD9kUbuRP85irLcUGpHJY4cLDh87f