A job relationship can be added called BOM Link which appears on the BOM Link tab in Mfg Order.  BOM links enables jobs to be related to other jobs without forming a formal assembly structure. 

A job in a BOM Link relationship can be a final job, can feed into one or more jobs, and can be fed by one or more jobs.  In the Job Tree you can tell if a job is part of a BOM Link by the BOM Link icons if the Job Tree Options to display the job link icon has been selected.  The BOM Link icons used in the Job Tree are:

1.        means that one or more jobs feed this job.
2.        means that this job both feeds another job(s) and is fed by another job(s)
3.        means that this job feeds another job(s)