Nginx - Search for static content in multiple directories?

Because of the way that our git repos are setup I have some static content that might be in one directory - and other content that might be in another directory. How can I ask nginx to search in two places for a static file like a stylesheet?

I originally thought that try_files had my answer - but I can't seem to get it to work.

try_files $uri /dir1/static/$uri /dir2/static/$uri @missing;