NSPs that offer block accounts usually allow these to be shared.
Although it's often against the rules, you can share virtually any usenet provider account, even unlimited, but the restriction is that both of you won't be able to log in at the same time. NSPs generally allow several domains per account to allow a subscriber to access his account from home, work, school, etc.
Most Dutch usenet providers allow account sharing. You must split the account resources. If your account allows a maximum of 8 connections and is throttled at 10megabits/second, then each of you can simultaneously download using 4 connections and 5mbs.