Hi
Too many unknowns. When you mean host you mean you want to call a 3rd party conferencing platform of what to have the conference ON the unit itself?
If the former - Where is the unit registered? Is it standalone? Is it behind a firewall?
Normally a Cisco video endpoint is standards based and can call out into a SIP URI (yourdomain.webex.com) or H323 URI?
You need to find out whether the 3rd party conference the Cisco Room Kit is attempting to join will accept an incoming call using SIP/H323 and if your Cisco system can reach/call across a network (that may be private or not) to that system.
If it’s the later then you need to check this ref Room Kit PLus
https://community.cisco.com/t5/telepresence-and-video/cisco-room-kit-plus-multisite-option/td-p/3780871 and
● 4-way embedded SIP/H.323 conferencing capability with MultiSite option is available on Room Kit with a option/license key. How will those 3rd parties be dialled in etc..
Thanks
ashish