Help wit the NPC

[Dustey]

Many of u have fooled around with this so can u help me, I am tying to make a bridge where if a guild member comes in and says 'Lower Bridge' the bridge will come down the screen a little ways. But I have been fooling around wit it and cant get i to work right. If u accidentally touch the bridge it will go even farther. The second thing I am asking for help is how do I make it so u cant go in to the water without the bridge bein there but when it i u can?

Thanks for ur Help