https://www.ibm.com/docs/en/ims/15.6.0?topic=parameters-sharedqxxx-parameter-procedures
IMS 15.6 - System definition - SHAREDQ= parameter for procedures
Use the SHAREDQ=xxx parameter in procedure to specify a 3-character suffix for the shared queues IMS.PROCLIB member, DFSSQxxx. There is no default for this...
imssystemdefinitionparameterprocedures