if you set the visible property for a control it will not sure up in datasheet view for a form.
So somehting like this in the After Update Event for the Combo box
Code:
sub mycombobox_afterupdate()
select case ucase(me.text)
case "A"
me.controlname4.visible = false
me.controlname5.visible = false
me.controlname6.visible = false
case "B"
me.controlname4.visible = true
me.controlname5.visible = true
me.controlname6.visible = true
me.controlname7.visible = false
me.controlname8.visible = false
me.controlname9.visible = false
end select
end sub