BUt then there really is no way to create a secure network, other than have lots of hookups. No matter what, if you have one large source that you want to connect to several smaller sources, a single attack will rob you of access to your large source in all provinces except the one with the source itself.
Not that I see this as a problem, it will still only take a single action to recreate the network... but all this talk of more or less secure made think there was a way. Of course, the safest way is to have multiple large sources supplying an entire network, but that's a luxury only few mages have.
EDIT: At any rate, thanks for answering my questions. I think I got it now.