Since Maya can only export a single animation track (with FBX at least) you have two options
-
Create one long track with all animations in a row. Then use @donmccurdy’s experimental PR to split up the animations after you load the model: https://github.com/mrdoob/three.js/pull/13430
-
Export the model multiple times with one animation one each version. Then extract the animations, save them as JSON
AnimationClips
and load them up alongside the model. If you go for this option you can use my loader to extract the animations: https://blackthread.io/loader/
Load up the model and click the save icon in the bottom left.
The better option here probably depends on how your model is set up in Maya. I would favour 1., but that PR is largely untested so you may come across problems.