It should be possible to merge streams after the (successful) build. This could be either "p4 merge" or "p4 copy" operation. Resolve options should be configurable. Pending changelists should be submitted. This way the CI build can be used to gate code changes and move code between codelines.

Also, if pre-build merge is applied, the pending changelist from that operation should be submitted. See https://issues.jenkins-ci.org/browse/JENKINS-11861.