In order to merge requests from multiple requests, you can use SE03 transaction. In SE03 this functionality is available under Requests/Tasks->Merge Object List branch of the tree. However there is a big pitfall while merging modifiable requests with unreleased tasks. If you try to merge objects from a modifiable request with unreleased tasks, some of the objects will not be included into the merge request. This is because your are only giving requests to Merge Object List but not tasks under tasks.
Recently i have needed an ABAP program which reports ABAP programs with the related code line. My intention was catching Select sql statements without in connection keyword. By this means i had aimed to find all select statements which are selecting from HANA replicated tables but has no HANA connection.
As you may know if you have configured SAP system routes in STMS correctly and requests are given the correct target system (either Target system or Target group), then each released requests will automatically transported to next target destinaiton in your transpor route. For example in a SAP landscape with Development->Quality->PrePoduction->Production configuration, a released Development request will be ready to be imported in Quality system.