Schedule to part disarm

HiAfter an increase in car thefts. I installed an outdoor contact sensor to our gates.I've set a schedule up so it disarms and re arms 3 times a week when the milk man comes.Thats not really ideal. As the whole alarm is off at that point and as he can have a 2 hour window leaves us unprotected somewhatIs there a better way other than getting the milkman to drop at the gates.