Run plan on pull request created for specific destination branch only

[Ben Hansen]

How do I configure Bamboo so that different plans run based on the destination branch of a pull request?

Currently, it seems that any pull request what so ever will trigger a plan when that setting is enabled in each plan, but I would like one plan to trigger for pull requests into develop, and a different plan to trigger on a pull request into master, and a 3rd plan on a pull request between sub-ticket and feature branches (we are avid users of pull requests, and don't want to change this).

We would like to automatically trigger the plan before the pull request is completed, and changes are merged into the destination branch, so manually monitoring the destination branch, isn't an option.