How to pull items with PulRequest merged to a specific branch

[JiraAdminTest]

I need to pull items that have merged PR to specific branches.

For example, I need to pull items when PR is merged to develop regardless of a PR being opened to master or not.

The following get me the items when ALL PR are merged which is not what I need.

Is there like a destination branch variable I could use?

development[pullrequests].merged > 0 AND development[pullrequests].open = 0

[JiraAdminTest]

If I could create a custom field that could pull this information as well that would be great. Custom field that look like:

pullRequestMerged in ("master")