Perhaps a little late on this subject but curious to know if this is a concern and should we be switching to BRS Carbon Blocks? Here is a video which BRS posted a while back.
Most normal RO systems adequately remove chloramine in the tests I have run, but if you are concerned, and before you buy expensive specialty products, I'd just get a cheap chlorine kit and test your RO effluent for chlorine (which also detects chloramine). If there is any, then it is time for a better carbon block.