You can use an inclusion list to specify the domains that VMware Horizon does not exclude from the results of a domain search. All other domains, apart from the primary domain, are removed.

A Connection Server instance is joined to the primary MYDOM domain and has a trusted relationship with the YOURDOM domain. The YOURDOM domain has a trusted relationship with the DEPTX domain.

Display the currently active domains for the Connection Server instance.

C:\ vdmadmin -N -domains -list -active 

Domain Information (CONSVR)
===========================
Primary Domain: MYDOM 

Domain: MYDOM DNS:mydom.mycorp.com 
Domain: YOURDOM DNS:yourdom.mycorp.com 
Domain: FARDOM DNS: fardom.mycorp.com 
Domain: DEPTX DNS:deptx.mycorp.com 
Domain: DEPTY DNS:depty.mycorp.com 
Domain: DEPTZ DNS:deptz.mycorp.com

The DEPTY and DEPTZ domains appear in the list because they are trusted domains of the DEPTX domain.

Specify that the Connection Server instance should make only the YOURDOM and DEPTX domains available, in addition to the primary MYDOM domain.

vdmadmin -N -domains -include -domain YOURDOM -add
vdmadmin -N -domains -include -domain DEPTX -add

Display the currently active domains after including the YOURDOM and DEPTX domains.

C:\ vdmadmin -N -domains -list -active

Domain Information (CONSVR) 
=========================== 
Primary Domain: MYDOM 
Domain: MYDOM DNS:mydom.mycorp.com 
Domain: YOURDOM DNS:yourdom.mycorp.com 
Domain: DEPTX DNS:deptx.mycorp.com

VMware Horizon applies the include list to the results of a domain search. If the domain hierarchy is very complex or network connectivity to some domains is poor, the domain search can be slow. In such cases, use search exclusion instead.