International endpoints

A client in California is expanding internationally and want their sales people in Korea and Ireland to have an endpoint connected to their on-premise system…no problem. The challenge is that they want their sales people to also be able to dial into their respective continents (Asia and Europe) from those phones. I know that if we route that call back to the US and then back to Asia or Europe the call quality is going to degrade significantly because of the number of hops the traffic is going to take. My thought was that a global hosted PBX company could be installed on a second line in the phone (Yealink T23G) allowing the sales people to make all the respective calls they need.

Does anyone have a recommendation or experience with an international Hosted PBX company that would work with us on this? Appreciate your recommendations! Thoughts?