Prior Record In Datasheet View

In my db I am tracking different stages for an event. I have a subform that is in datasheet view. The last field (current) is a yes/no check box that says that this entry is the current stage of the process. In one of the fields I have a afterupdate event that says me.current = true. But what I need is to change the previous entry to show that stage's current to be false.
Does that make sense?

Date Event Location Current
02/01/07 Drying Dryer X (when next event added this =false)
02/05/07 Bagged Warehouse X

Up until I enter the 02/05 entry the 02/01 entry was the current stage and I want a check in the current box. But when I enter the 02/05 entry that now becomes my current stage so on the 02/01 event then current = false and on the 02/05 event current = True. I can get the 02/05 event to show current = True but how do I make the 02/01 current =False?

Thanks,
Rick