Get-ADGroupMember limitations

Hi All,

I am trying to run the following query:

get-adgroup -Filter * -SearchBase "OU=Test,dc=domain,dc=com" | get-adgroupmember | get-aduser -Properties * | Select Name,postalCode

and get the following error: Get-ADUser : A referral was returned from the server

Test OU contains Universal Distribution Groups with memebers from different domains in the same forest.

So I've figured running agains GC server should fix it but I've hit a limitation:

get-adgroup -Server dcgc01.domain.com:3268 -Filter * -SearchBase "OU=Test,dc=domain,dc=com" | get-adgroupmember | get-aduser -Properties * | Select Name,postalCode

and got the following error: Get-ADGroupMember : The operation is not supported on Global Catalog port.

It's Server 2008R2 with PS version 2

Thank you,

Naz