Cisco ISE 2.2 with Multiple Phones on one interface

[jm.virtual01]

I have a problem with the phone system, connected to the ISE. The phone system contain two more phone devices behind the phone system and this phone system is connected to the network jack, i have assign multi host authentication mode but here, there are multiple voice domains. How can i authenticate multiple voice domains from a single interface?

[hslai]

Please review Identity-Based Networking Services: IP Telephony In IEEE 802.1X-Enabled Networks Deployment and Configuration Guide > 2.3.12 Host Modes 

As you have 3 phones, I would suggest to use multi-auth host mode. Please note that each switch interface may have one and only one voice VLAN.