How to compare and render currently subscribed collection?

How to iteratively compare items in a subscribed (filtered) collection with another collection and render results?

Collection A: Apple, Oranges, Bananas
Collection B: Apple, Lemon

Output : Apple

Do I need another collection to store the result, or simply render as list if storage is not needed?

Also, how to render a subscribed collection ?

Meteor.publish(test, …)


Render test collection?