Yes, but I think it is only for United Premier Access. I did SJD-IAD-YYZ-YUL two weeks ago and used it, but the IAH-YYZ segment was with UA.

As it was mentioned earlier, you should be able to make it, especially if you have Global Entry. The only bottle neck could be the security line after re-checking your bags (although not anymore needed if they are labelled with the Transit tag) I think that if you go outside instead of following the connecting passengers signs, you can then get back into the terminal through the other security door and that might save you some time. Haven't tried it yet, maybe next month, I will have a four hour layover at IAH on my way back home.