Third party updates will synchronize to the downstream server along with the normal updates. If you're looking to leverage some of the client tools (Computer Inventory, Update Management, etc) then you may start by looking into an automation server at that site. Here's some information on this role.
There's some additional information in the Advanced Deployment Scenarios section of the Patch Manager Administrator guide.
Thanks for the information.
My replica server is set to download updates from Microsoft instead of the upstream HQ server. Will this setting work with 3rd party updates? My guess is it will not.
Edit: to sync the 3rd party updates to the replica server, do I need to add the replica server to my PM console at HQ in Stockholm?
Edit 2: I've set the replica server to download from the upstream server instead, but my question above still stands: do I need to add the replica server as a WSUS in the PM console. I still need to publish 3rd party updates to both servers, it doesn't suffice to publish to just the upstream server?