Here's an interesting one for you folks... I have a HABTM (has_and_belongs_to_many) relationship between "Dogs" and "Trips". My goal is to find two result sets: 1) Dogs that have been on at least 1 of the last 3 trips and call that @dogs_current 2) Dogs that have NOT been on any of the last 3 trips and call that @dogs_old I found that I can find what the last 3 trips are by doing this in the Trip model: named_scope :last3, :order => 'date DESC', :limit => 3 But not sure how to use that list get 1 and 2. This hack works, but it seems ugly. There must be a better way! :) @dogs_current = [] @dogs_old = [] @dogs.each do |dog| if (Trip.last3 - dog.trips).size < 3 then @dogs_current << dog else @dogs_old << dog end end Any ideas? Thanks! -Cam