[Rules] Allow modification of Message Templates in Dynamic Variables

I'm trying to build a rule that uses AI topics to send a message template response when certain topics are used.

I want to send an existing message template, but add a "sent using AI" disclaimer at the end of the message.
Right now, the only way to accomplish this is to save a near-duplicate of the Message Template (meaning I now have two copies of the same template to maintain).

I've love the ability to Create/modify Message Templates in dynamic variables to allow me to "stitch" two or more templates together - that will allow me to send a dynamically built message template containing first the content of the message I want to send, followed by a generic disclaimer that would only be used when sending messages powered by AI Topics