Role Based Task Assignment Automation

I am currently using the Workload balancer to assign my users using the bulk assignment tool, which has been helpful; however, the way that our roles are configured it is conducive to allow for automation. For example, task 1 is assigned to Brand Manager I and task 2 is assigned to Brand Manager II, so there is no overlap and the system easily make that designation. Unfortunately, I have not been able to figure out on my own how to get the system to automatically assign the users to the tasks. Each user is assigned a role and each template has the appropriate role(s) identified for the tasks.

Has anyone been successful in setting up automation for their projects in a standard business license? Any recommendations?

TIA! 

Danica