How do I show statistics per ad per group?

I apologize if this is somewhere in the docs. I've been searching because I feel like this is something that would have been asked before but am having no luck finding it.

I have fairly simple ad needs so don't need channels. I have various areas of the site that have ads and have made a group for each area. Because I have tried to be consistent with ad sizes as much as possible, I could end up with one ad being in multiple groups. I tried it as an experiment and the statistics shown on the ad don't say what group the views/clicks are coming from. This isn't good because I need to be able to see how an ad is performing in each area of the site.

Is there a setting or something I'm missing? I'd really rather not have to create a separate ad for each group if I can avoid it.

Thanks,

Michelle