multiple loops with multiple thumbnails

Hello all

basically what i wanna do is have a website with 3 different loops and different thumbnails, however, its not as simple as it sounds: basically my theme has 3 loops:
one for the latest article, one for older articles and one loop for special banner like announcements that are more “permanent.”

so for the first post and older articles basically when a posts gets bumped down for a new one, the thumbnail must be a different size than when its in the New post loop. how can i manage this?