Need trigger help please: Forcing player to build a building next to a Unit

[Kevin]

HI!

I am trying to figure out how to do this trigger and I can't figure it out.

Basically, I want to make it so that a Road can only be build next to another road, and that a Wall can only be build next to another wall and within 800 distance from the Town Hall.

How do I set up a trigger to do this?  I was told once that it was a simple trigger, detecting distance from another unit of the same type, and then refunding the gold spent if the distance is too far.  But I can't figure out what that stupid trigger should look like!!!!!!

Can anyone help pls? tyvm

[X]

This sounds tricky but probably isnt to difficult, ive never done this sort of trigger and really only know how to do AOS map triggers, ill try to help though.

To make it so a player could only build a wall next to a town hall it would probably look something like this

Event:A unit comes within a 1000 Radius of Townhall

If Triggering Unit is Equal to Wall Equal to True then do multiple actions: Kill Triggering unit and give the message: You can't build to far from your Townhall

Something like that, i'm not sure how to make a road be built next to a road but if you email me the map your working on to theblob311@yahoo.com then I will look at it and experiement on how to do it.