I am currently a CRM Plus user. 

I run a staff augmentation business model whereby I hire a contractor and place them at a client location. That contractor needs to create weekly timesheets that, when submitted, route to a client approver for approval. I then submit the invoice to the contractor employer and they invoice me and then I invoice the client. 

Does anyone have suggestions on how I may do this? Both the timesheet submitter and approver our outside of my organization. I thought about client users through projects, but the timesheet approval function is global and I do not need/want all of my normal project timesheets to go through approval.