Allow grouping by datasource

It would be very useful for my organization to be able to group by the existence of a datasource - for example, servers with the "Apache" datasource could be sorted into a "Webservers" group or servers with the "Mysql" datasource could be sorted into a "Database" group. We're sorting by property right now so we can use dynamic groups, but it'd be really cool to be able to do things through datasources rather than properties.