Your network contains a Active Directory Domain Service (AD DS) forest named contoso.com. The forest root domain contains a server named server1. contoso.com.
A two-way forest trust exists between the contoso.com forest and an AD DS forest named fabrikam.com. The fabrikam.com forest contains 10 child domains.
You need to ensure that only the members of a group named fabrikam\Group1 can authenticate to server1.contoso.com.
What should you do first?