Suggestions on use of PeerReview

We've been using Peer Review for about two months and the team has really taken to the tool and the process. However, we've run into an issue that is a little perplexing. We seem to have difficulty completing reviews. By this I mean that most reviews go on with useful discussion for longer than is probably helpful. This is a nice change from the barely minimal code reviews we were doing before turning to Peer Review.



My question is: Is there a best practice means of terminating a particular review without stifling the utility of the review? For the moment, I have set the default review deadline to 2 weeks and instructed the review authors to convert reviewers to observers unless the reviewer has logged defects during the review. This seems like a work around and I'm looking for something more like a "button" or trigger that terminates the review.



Any input will be greatly appreciated!