No, but that would make a great feature request.
We're getting ready to do some "show me how you use it" sessions with existing AC users to learn how to make the on call calendar better. We'd sure love your participation! All this is is a 1 hour GoToMeeting where you talk us through how you're using the on call calendar, tell us what you like about it, what you don;t like about it, and any ideas for improving it. People who participate in these "show us" sessions next week will get 2,000 thwack points; plus, there is a likelihood that your feedback will directly improve the ease of use and usefulness of on call calendars down the road. You can email me privately at firstname.lastname@example.org to set up a time or learn more. Thanks!