You are network administrator for an Active Directory forest with a single domain. Then network has three sites with one domain controller at each site. You have created and configured sites in Active Directory Sites and Services, and replication is operating normally between sites. You configure two universal groups for use in securing the network. All users are members of one universal group or the other. After configuring the universal groups, users at sites 2 and 3 report slows login and slow access to the corporate database. Users at site 1 can log in and access the corporate database with acceptable performance. You want to improve login and resource access performance for users in sites 2 and 3. What should you do?