Defining Ticket Queues/Teams for Employee Central - C4C Integration

This question is related projects where we integrate SFSF Employee Central to C4C for Employee Support functionality. My understanding is that Queues or Teams are driven by the org units. Is this assumption correct or is there a way to create queues and teams and have a user part of multiple queues or teams. I know this is a very basic question but we may have a potential issue for the Employee Central Service center integration where we replicate employees and org units from EC to C4C. The customer wants to have queues per their internal employee support processes and way they are currently organized. The org units employees currently belong to in EC does not help them. So, we end up creating a separate org structure in C4C to accommodate this. However the point to point integration between EC and C4C does not allow mapping of employees to org units and also we cannot manually make changes to employees since this gets locked down due to the integration being turned on. Regards, Sathish Ganesan