"ReadProjectSecurityGroupMembers" takes in the project server group UID as a parameter(which you'd find in the URL ../AddModifyGroup.aspx?groupUid=..., or you can use an association page where you'd read it from, instead of hard-coding in the workflow).
In the sample code, we intended to use Team Leads as the group we read resources from, but then we decided to use Portfolio Managers instead. That's why, in this statement "public static readonly Guid TeamLeadsGroupUid = Library.PSSecurityGroup.PortfolioManagers;",
TeamLeadsGroupUid remained as a variable that we used to hold the GUID we are interested in(in our case, we are using the out-of the-box Portfolio Managers group which you can find in the Project.Server.Library.dll).
In the scenario you've described, there are 2 options:
1. Simple - Create only one Project Server group and add all approvers to it. Then, ask the project creator to fill in the project department and only have one approval process (based on project department).
2. More complicated - Create multiple Project Server groups, one for each department. In the workflow, create a custom activity that would read the project owner and its department(as it's not coming from the AD), then, based on the department, you'd send
different groupUIDs into the approval process.
Hope this helps.
