Able to set home page?

Using this module with Group context: Path prefix is very close to what I need for managing microsites using Group. One thing I haven't been able to figure out is how to set the default page for a group. For example, I could have a group with a site prefix of /site1, so a page I created in that group called "About Us" might get the path /site1/about-us. If I visit just the prefix (e.g. /site1, I see the main site's home page, instead of content from the group.

Is there a way to choose a node to be the group's "home page" and have that displayed when just the prefix is accessed?