Why does your solution "feel stupid"? It's the most straight forward and workable solution.
You have two options:
a) Whitelist all domains you want (if you only want specific 'work' domains)
b) Blacklist those you do not want
You have two options:
a) Whitelist all domains you want (if you only want specific 'work' domains)
b) Blacklist those you do not want
In the situation I need it in, that's an OK solution, but I was interested in finding out if there exists a better solution.