A Director is recommended, but not required, when using PIC/Federation/Remote Access. Ditto when using multiple pools. All internal OCS servers act as a Director by default, so you can either point your SRV records towards one of your EE pools or deploy a Director (or pool of Directors) to use for the SRV record.
This can become complex when you start designing for multi-national deployments, so it's tough to go into further detail without more information.