Single instance from a loop

Hi all,

I have an archive that contains lots of articles - some of these articles have a logo file included showing the company logo.

I want to create a section that shows which companies have articles and display a single copy of the logo (even if there are 20 entries with the same logo).
Then, when that logo is clicked, they are taken to a page showing all the articles from that company.

I was thinking maybe I should be using a taxonomy to group the companies, but I can’t get them to display this way.

Any pointers on how to achieve this would be greatly appreciated.