Configuring Differant GRT settings for Full and Incremental Exchange backups

Environment:

BE 2012 SP2

Exchange 2007 SP3 CCR cluster

Windows 2008

Problem:

GRT Incremental backups take 3 days to complete while the full only takes a 1 day.

According to this Symantec article http://www.symantec.com/business/support/index?page=content&id=TECH65616 I should turn off GRT on the incremental backups.  This solution would be acceptable to me but I can't figure out how to do this in BE 2012.

There is only one GRT setting for full or incremental.  I have been testing with placing the incremental job on hold and creating another set of jobs for the cluster where only the incremental would run and the full would be on hold.

Any idea how I can create different GRT settings for incremental job?