This is a great extension. Manually changing the containers was a serious limitation for me. This perfectly isolates my work, banking and personal surfing.

It will be absolutely flawless even if you implement a very rudimentary wildcard support.

Something like (*.google.com) should work for:

maps.google.com
mail.google.com
plus.google.com

To limit the complexity, you need not support partial wildcards, like (m*.google.com) or wildcards in the suffix (example - google.* for google.in, google.com etc).

Good luck! :) Hope to see some sort of wildcard support in future updates.