Set custom environment variables via registry to appear in remote session

For specific enterprise scenarios, it is required to be able to set custom environment variables within the remote session from the client machine on which the RAS client is started. These additional environment variables should be setable via user registry (to support multiple concurrent users on source machine - e.g. a terminal server) on the client-side and be read on launch of a published desktop or app. Changing these variables during an already running session must not be reflected within this running session but picked up by sessions which get started afterwards.

In addition, this should include the possibility to set/define additional remote environment variables via setting the above registry keys per published desktop / published app via a client-side executed powershell script (definable per published desktop/app) which is synchronously launched directly before the connection to the published desktop / app is launched - so that dynamic scenarios can be covered.

Also this should include the possibility to override standard environment variables within the remote session - like setting the %clientname% variable with a custom value from the client-side. (This would enable the scenario where a pool of non-personal (auto-reseting on logoff) VDI clients are used to run host applications which require a static hostname (e.g. POS solutions which assign their networked periphery like bon printers, mifare readers, etc. solely on the workstation name). --> With Citrix this is possible and we are using this actively.)