Return the latests N posts for each primary tag

I’m building a blog catalogue for a travel page. The first tag for each blog is the continent. I basically want to get the last 3 posts for each tag (i.e. continent) without having to repeat ‘get posts filter X’ for each tag 7 times.

Any ideas to automate or make this dynamic? In case I decide to change the first tag to something like countries.

Thanks!