allow Workfront role or sponsor be a recipient on proofing workflow stage

Currently, when you set up an automated workflow on proofing, you have to assign a specific user to the workflow stage. We have over 500 possible reviewers and approvers, we do not want to tell the proof creator to select from 500 possible workflows. We want the workflow to instead base it on an object on the project, eg the sponsor, or a job role related to the project eg a creative director.

So for example, stage 1, assign a $$project.sponsor (just thinking how $$USER.ID is used on reports) so it's like a wildcard and when the user selects this automated workflow, it picks on the name that's the project sponsor on the project.