SMTP - connection refused

I'm monitoring some very busy SMTP servers that handle all our incoming email. Because they are so busy, at times, Xymon will get a connection refused condition when testing SMTP, which generates a red alert. Its fine at the next test cycle, but the false alerts concern me. (People get used to seeing false alerts, they ignore the real ones.)

Does anyone have any suggestions? Is there I way I can alter the SMTP test to not generate this condition as an alert, or perhaps an alert script that won't send out an email?

Martha McConaghy Marist College