Wordpress同一站点的多个路径

When using WordPress multisite you have:

domain.com/site1/blablabla 

and

domain.com/site2/blarg/blarg

Those are different sites and they use different path. I am looking for a way to have one site handle multiple paths. Suppose we have:

domain.com/tutorials/lalala

And I want it to be handled by site1. Is it possible? I know that one could get somewhat similar effect by disabling multisite and simply using custom urls on all pages, but it is not an option currently, as there are quite some sites established and merging would be too cumbersome.

There is a plugin WordPress MU Sitewide Tags Pages that creates a central blog where posts from all network sites are shown in the front page. It might be something similar to your needs.