Expense Report Approval - Project based (how to route it to key members - project role)

Organization Name (Required - If you are an Oracle Partner, please provide the organization you are logging the idea on behalf of):

Description (Required):Hi, We have requirement to setup workflow based on project based expense items

Use Case and Business Need (Required):

for example: 1 st stage: it should route to Project Manager (This is working as per seeded setup)

2nd stage: it should route to Project Key Members (I used the string Project Team Member.Team Member User Name and it partially worked) it routed to 4 users (2 key memebers, 1 project administrator, 1 project participant).

Now, the issue is it should not route to Project Administrator and Project Participant. How to restrict this? Is this even possible?