You could set up an Internal Spammer rule in your Security Settings that will automatically block the sender for a specific amount of time...say, if they send more than 100 in 60 minutes, block them for 30 minutes or more.
Why are you disabling the user/domain and when do you re-enable them? If you limit them for a specific amount of time, an Internal Spammer rule may do the trick for you.
Derek Curtis
COO
SmarterTools Inc.
www.smartertools.com