Maybe I've been working too much this week, but I can't seem to
figure out how to do what I want with a sortlist option, not
even after STFW and testing for a couple of hours. In case
it's an obvious mistake, I'll give the attempt first:

sortlist {
{10.98.192/18;};
{!10.98.192/18;};
};

The effect that I'm after is that clients inside the 10.98.192/18
netblock receive A records from that netblock first, and that
clients outside that netblock receive A records *outside* of
10.98.192/18 first.

It works for the first case, but not for the second. In other
words, clients outside of 10.98.192/18 are receiving just
the standard cyclical behavior. The relevant RRSet is:

stealth.example.com. 3600 IN A 10.98.16.142
stealth.example.com. 3600 IN A 10.98.200.4
stealth.example.com. 3600 IN A 10.98.200.5
stealth.example.com. 3600 IN A 10.98.200.6
stealth.example.com. 3600 IN A 10.98.16.141

What am I missing?

Thanks.