The 4 "Ryan's Wedding" episodes appear to exist both as episodes 5x13-16 of the main series and as a separate series ?
Million Dollar Listing: New York vs Million Dollar Listing New York: Ryan's Wedding
A quick browse of the bravotv.com site suggest they belong in the main series and the RW series should be deleted.
But it's Bravo realiCrap, so who knows what they'll say tomorrow :-)