Try having the job release a simple self-completing task if it gets a 1. You can add this task as an external to your other application. So:
=================================================
APPL APPLA
JOB C02465G
RUN TODAY
RELEASE ADD(CJOBS.GROUPX) COND(RC(1))
ENDJOB
JOB CJOBS.GROUPX TASK SELF COMPLETING
RUN TODAY
ENDJOB
==========================================================
APPL APPLB
AIX_JOB CJOBS.GROUPX EXTERNAL APPLID(APPLA) SCHEDULED(TODAY)
TAG HM_APPL=APPLA
RUN WORKDAYS
RELEASE ADD(C02455H)
ENDJOB
JOB C02455H
/* X_TEST _ GROUP
TAG CJOB_1
DATASET C02465.JCL.CNTL
RUN TODAY
RELEASE ADD(C02465A)
RELEASE ADD(C02465B)
RELEASE ADD(C02465C)
ENDJOB
======================================================
This would be two applciatoins, APPLA and APPLB. I've taken the liberty of converting your task into a z/OS job, and giving it a new name (using the next letter up in the alphabet). What will happen is, if C02465G gets a return code of 1, it will release a task that will act as your external in APPLB. If it gets marked as complete, then the external releases C02455H.
Of course, from a purely design standpoint, you could make this a little cleaner by simply releasing the second job only if the first job gets a 1, then using a cleanup task to clean the second job up at a specific time if it never runs. That could look something like this:
=================================================
APPL APPLA
JOB C02465G
RUN TODAY
RELEASE ADD(C02455H) COND(RC(1))
ENDJOB
JOB C02455H
/* X_TEST _ GROUP
TAG CJOB_1
DATASET C02465.JCL.CNTL
RUN TODAY
RELEASE ADD(C02465A)
RELEASE ADD(C02465B)
RELEASE ADD(C02465C)
ENDJOB
JOB CLEANUP TASK SELFCOMPLETING
RUN TODAY
DELAYSUB 23:40
ESP AJ C02455H COMPLETE APPL(%ESPAPPL..%ESPAPGEN)
ENDJOB
======================================================