A few techniques come to mind, however I found a technical conference paper at the SAS support
http://support.sas.com/ website which discusses parallel processing. And for your successor SAS program, you can use a technique that detects the presence (or lack) of "gate" file(s), such that when all are present you proceed with your follow-on SAS program execution.
Or, maybe your enterprise already has a job scheduler specifically for this purpose - maybe ask around.
Regardless, I'm sure you can find a suitable tool/technique with SAS - take advantage of the support website and its resources.
Scott Barry
SBBWorks, Inc.
Parallel Processing on the Cheap: Using Unix Pipes to Run SAS® Programs in Parallel
Ted Conway, Ted Conway Consulting, Inc., Chicago, IL
http://www2.sas.com/proceedings/sugi28/114-28.pdf