Need help for Unit shared resource multiboard problem

Level 5
May 29, 2013
If a player shares a unit while using an existing multiboard, a resource multiboard will be created, causing the existing multiboard to disappear.
How can I make existing multiboards reappear? I know the multiboard show and hide functions, but I don't know how to use them.
In most of the cases I tested, the existing multiboards don't appear, only the resource multiboards are hidden. Even if I assign an existing multiboard as a variable and make it show only.
I would be very grateful if you could create an example map.