Ok, use variables in this one. When Link would be in a room called "south", add "global.currentroom=south" in the room create - event. Then let's say, there's a room called "north". Now, in the room create - event of room "south", add
if global.currentroom=north
instance_create(x,y,objLink)
global.currentroom=south
then in the room "north", add in the room create - event:
if global.currentroom=south
instance_create(x,y,objLink)
global.currentroom=north
Hope you got the idea. I'm not very good in explaining these things