there is no built in facility. there are some apis one could write code to, to accomplish this task.
(I wrote a couple different integrations for Salesforce Service Cloud).

there are also a couple good companies that have general purpose integration tools that work with RTC.
I'm not sure about ServiceNow.   Tasktop (Sync) and Kovair (Omnibus) are two I have worked with.

Doing it by yourself is doable, with reasonable support.. Maintaining it is always a pain!...
it is not for the faint of heart however.
http://www.ibm.com/developerworks/rational/library/10/synchronizedatarepositoriesbyusingtherationalteamconcertitemconnector/index.html?ca=drs-