Support conditions on DVCS triggers

I would like to add a condition on a DVCS trigger, specifically for Pull Requests being created / accepted on specific branches. This is so we can perform transitions for tickets only when they are looking to be merged into "develop" or "hotfix" branches, not during incremental code reviews or integration PRs.

Please see my question here: https://answers.atlassian.com/questions/29263153/how-do-you-trigger-a-workflow-triggers-on-a-pull-request-action-to-or-from-a-specific-branch

Another use case for this feature request is the following one:

• let's assume that a Jira application is configured with multiple DVCS applications (for example: Github, Bitbucket and Gitlab)
• it is not possible to configure the workflow trigger to be executed only if the pull request or commit from Github, but not from Bitbucket/Gitlab. In other words, it is not possible to differentiate where the trigger came from.
• it would be great if we could add some condition to the trigger so that it is only executed when it came from a specific source