Actually you can =P
The brush would need to be a func_train, once it reaches a path_corner, the next path_corner will be triggered, if you have something like a target_relay with the same targetname as the next path_corner it will be triggered as well =)
I found that out screwing around with entities, that little trick has a LOT of applications

(thats how I control when to open elevator doors in one of my maps)