OTL - how to configure for multiple assignments that need different element lists

Summary:

How to restrict available elements per assignment in OTL when employee has multiple assignments

Content (required):

Employee has two assignments and needs to use OTL for both. Job 1 allows entry of elements A, B, C, Job 2 allows entry of elements D, E, F. What is the best way to configure OTL so that the appropriate elements are selectable for each assignment?

We've tried HCM Groups, but that only works per person, not per assignment.

Version (include the version you are using, if applicable):

21D

Code Snippet (add any code snippets that support your topic, if applicable):