We created a group Tumblr page and tagged all the posts so we could search by topic. I can't seem to figure out how to do this just for our page. The tags are fairly common and pull up all kinds of posts from other blogs.
Every tag has two URLs that only show the posts on a specific Tumblr.
Let’s say the Tumblr is called
You could also search for the occurence of a string (which includes tags):