Hi Edward,
Based on the documentation, the current limit of three address transformations per trunk is a platform limitation.
Using more advanced regular expressions can sometimes help consolidate multiple rules into a single transformation, although that can also make the expressions harder to read and maintain. If you need more than three independent transformation rules, the practical workaround today is to split the routing across multiple trunks.
I also found there's already an existing Idea requesting that this limit be increased to a configurable value:
https://genesyscloud.ideas.aha.io/ideas/CERTNG-I-1913
Although the use case described there is multiple divisions requiring different transformations, it addresses the same platform limitation. If it aligns with your needs, I'd recommend adding your vote and sharing your use case in the comments.
Since you've already reached this limit, it's also worth checking the comments on that Idea. You may find other customers facing the same challenge, and adding your scenario can help demonstrate the demand for this enhancement.