Script to pull items with PR merged to specific branch

[JiraAdminTest]

I need to pull items that have merged PRs 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.

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

Is there a script I could use to create a custom field that could pull this informationt. Custom field that look like:

pullRequestMerged in ("master")