Link two GIT branches to the same task?

[Infrastructure Solutions]

Good Day

I have two GIT Branches, in two different GIT Repositories, one of them stores the designs, and the other, the code.  I want both of them to reference and link to the same task, as they go together, BUT, when I commit using the task key, I only get the latest branch, in that repository to show up.

Have I missed something?  This seems like fundamental functionality, so I'm sure I'm missing something in the setup.  If by some off chance this isn't included functionality, how long until it's resolved?

Thanks