That's not a good idea having a REXX program waiting for a batch job to come to an end before continue processing. What would you do if your first job is delayed for whatever reason?
If you really need a sequence, then simply use your scheduler tool. Every shop has such a tool as Control M, OPC, TWS, or CA-7.
If you are not allowed to use it, you could convert your jobs to a single job with several steps. The conditional execution of these steps could then be defined by the parameter COND= of the EXEC statement.
Or you could simply add a final step to every job invoking IKJEFT01 using the SUBMIT command to fire the follow-up job. By clever use of the COND= parameter on this step you can cause a serialization of all of your jobs in a predefined sequence.
There are 10 types of people in the world: Those who understand binary, and those who don't.