< Begin soapbox rant >
I have been transitioning my users away from the complicated SET RELATION TO and INDEX ON methods of selecting and joining data and into the slightly more straightforward method of SQL queries. Now the "report writer we've all been waiting for" comes along, and insists the we go back to SET RELATION TO and INDEX ON. This simply isn't necessary. Don't assume we're stupid if we dont provide a relation. Just process the whole damn target alias, letting "Print When" sort out the relations. Yes, this is sub-optimal for speed, but it does make it more possible for end users to develop custom reports that they might not get done otherwise.
< End soapbox rant >