Graceful Disconnect Query

We’re using Distributed Cloud and have this setup to load balancing between 2 Origin Pools where each origin pool contains servers at each of our 2 Datacenters.

in the scenario where we have:

• active users with persistent session at each site
• requirement where we need to mark one site to not accept any new connections
• To allow existing users a grace period of x minutes before we force disconnect
• Requirement to perform patching on the servers at this particular site while users connect at the opposite site

how is this achieved in Distributed Cloud. Is there an option anywhere to gracefully disconnect and set a maximum time to wait before any remaining active sessions are disconnected?