When looking for JCL procedures, the parser uses the JCLLIB statement, if present. If there is only one copy of the searched procedure, that copy is used. Otherwise, if more than one copy is available, the libraries specified with the JCLLIB statement are used to pick the right one.
Path to the JCL file: <workspace_path>\Sources\APP1\MYJCL\MYJOB.JCL
//MYJOB1 JOB ... //MYLIBS1 JCLLIB ORDER=CAMPBEL.PROCS.JCL //S1 EXEC PROC=MYPROC1
In this case the procedure <workspace_path>\Sources\APP1\CAMPBEL.PROCS.JCL\MYPROC1, if present, will be used.