New Macro for External Tools / Create Pull Request from IntelliJ

Hello there

I would like to create a pull request from IDE. For that I configured an external tool that calls my browser to open the URL for creating a pull request (in my case stash).

To make life even more easy I would like to transmit the current branch in IntelliJ as a parameter to the given URL. Since there is no macro for that available I would like to know how I could achive that?

The URL is like

https://URL_TO_STASH/PROJECT/pull-requests?create&targetBranch=refs%2Fheads%2Fdevelop&sourceBranch=refs%2Fheads%2Ffeature%2F$$$myBranchName$$$

And $$$myBranchName$$$ shall be the current branch.

Anybody an idea?

Greetings
Stefan