Reset Page Number On Group

Chris Hays has been putting out some great posts on his Blog lately. Here's one that stumped me in the past, how to reset the page number based on group. This is the situation where you want to use a page break at the end of a group and have the page number restart. This situation has come up on reports before and I've never had luck solving it. I haven't given it a shot yet but hopefully it works and I'll be testing it out next time I hit the scenario.

Thanks Chris!! Keep up the good work!