Credentials passthrough from zero desktop to RDP session servers

Hello,

I have a configurational issue.
In our company we are using two RD servers.
Both seperate from eachother, allowing one to be the backup (by users choise) of the other in case of calamities.

We're using WMS with thin clients for management.
The thin client starts up and asks for authentication (in the generalsettings of the WMS policy).
That can be anonymous or any username.
After that the user needs to select a RD server to logon to (the live or the backup server).

Is there any way to, or disable the first authentication (allowing access to the zero desktop) or to use the first credentials to passthrough to the underlying sessions (the two RD servers)?

Help would be greatly appreciated!

Best regards,

Pascal