You would have to create a synchronizer that uses the API's of the tools to do the synchronization. With respect to Luis's answer, I think it is premature to assume how this could be done in detail. It basically depends on the available APIs as well as the possible approaches how such a synchronizer can work as well as design and implementation decisions. RTC actually has a synchronizer framework that could be used as well. This would require RTC to be able to talk to the salesforce API. Partners have created many integrations based on different approaches and technologies.

 Such integration would have to be via OSLC, but Salesforce needs an adapter, see https://archive.open-services.net/software/salesforce/index.html