code: public void addCorrespondingSipSession(MobicentsSipSession newSession, MobicentsSipSession correspondingSipSession, String headerName) {
  		if(JoinHeader.NAME.equalsIgnoreCase(headerName)) {
  			joinSession.putIfAbsent(newSession.getKey(), correspondingSipSession);
  		} else if (ReplacesHeader.NAME.equalsIgnoreCase(headerName)) {
  			replacesSession.putIfAbsent(newSession.getKey(), correspondingSipSession);
  		} else {
  			throw new IllegalArgumentException("headerName argument should either be one of Join or Replaces, was : " + headerName);
  		}
  	}
docs: Add a mapping between a new session and a corresponding sipSession related to a headerName. See Also getCorrespondingSipSession method.
  @param newSession the new session
  @param correspondingSipSession the corresponding sip session to add
  @param headerName the header name