I have banner ads stored in a channel and these are associated using a single entry Playa field with clients stored in another. I need to display random banners on a page but without ever showing more than one banner from each client.
Channel entries has no concept of 'Group By' so how am I best to go about doing this?
In the end I wrote an extension to do this though the answer below would work equally well. You can download the 'Group By' extension here - https://github.com/ninefour/group_by.ext.ee_addon