I'm not sure if it'll work, but how about the spell Mystic Shield from the FR Anauroch book?
It "prevents all spells and SLA's of 6th level or lower from affecting the recipient"..
Anti-Magic Field, being a 6th level spell,
should be covered by that.
On the other hand, Anti-Magic field states that any and all magical effects within its area is supressed and non-functional..
Question is then, which spell takes "priority"?
If it works, it's a go-to easy-peasy fix for all the anti-magic hating sor/wiz..