Is there any way to create a union specific message template?

Summary:

We have 3 separate Unions in our company and the Job Field/Organization/Location is not finite enough to specify which union the message template would apply to. Is there any other way to alter the send context to be able to have differing templates for each union?

Content (please ensure you mask any confidential information):

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

25C.1.1

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