You can create DNS application directory partition to host DNS zone containing user account entries with the use of NTDSUTIL.EXE and DNSMGMT.MSC tools.
Note 1: You can also create a custom Active Directory partition by using the DnsCmd command.
Note 2: Implementing DNS Application Directory Partition
1. Login to the forest root domain controller using your forest root domain admin account or enterprise administrator account
2. Start the command prompt.
3. Type NTDSUTIL and hit enter
4. Type PARTITION MANAGEMENT and hit enter
5. Type CONNECTIONS and hit enter
6. Type CONNECT TO SERVER <forestRootDomainControllerFQDN> or
<childDomainDomainControllerFQDN> ex. CONNECT TO SERVER
DC01.AMRS.SYNERGIX.DS
1. Type QUIT
2. Type LIST to view all known naming contexts
3. Type CREATE NC DC=dnsADPUsers,DC=Local domainControllerFQDN ex. CONNECT TO SERVER DC01.AMRS.SYNERGIX.DS
1. Type LIST to view all previously known naming context and the newly created DC=dnsADPUsers,DC=Local naming context
2. Do NOT add another replica for the naming context DC=dnsADPUsers,DC=Local This DNS Application Directory Partition is for a special purpose DNS zone and we wish to avoid Active Directory Replication delays. A backup of this DNS zone's content can be maintained in a secondary DNS zone on any DNS server.
Reference:
https://synergixdesk.zendesk.com/hc/en-us/articles/202927548-Create-DNS-application- directory-partition-to-host-DNS-zone-containing-user-account-entries