To hide domains you need to type the following command...
"\Program Files\VMware\VMware View\Server\tools\bin\vdmadmin -N -domains -exclude -domain <DOMAIN NAME> -add"
on the connection server / broker.
To list exclude list type the following command...
"\Program Files\VMware\VMware View\Server\tools\bin\vdmadmin -N -domains -list"
To show all the commands that you can use with vdmadmin.exe type the following command...
"\Program Files\VMware\VMware View\Server\tools\bin\vdmadmin -help"
Hope this helps!