Which is something that sounds fine but, IMHO, practically speaking it's not really going to work. Most of the time you're going to end up having to page for the systems your team doesn't own for any non-trivial issue.
When your team owns an application you have no background knowledge in, and it uses a technology that you haven't touched since you attended a training 18 months ago; I would assume that your on-call response for any non-trivial issue would still be to page someone for help.
