Changing priority on duplication jobs BE 2012

I am running BE 2014 SP1.

After a backup I run two duplication jobs.  I want to adjust the priority of these jobs.

I tried using the GUI to adjust the prority but this changed the priority of the backup job and left the duplication priority at medium.  I want to adjust only the priority of the duplication jobs.

Is this possible, if so how?

Thanks