Problem: I have big region 'plot'. Inside i have multiple region 'house_1 .. house_x'. Im using ARM plugin to buy/sell regions. My plan is to make that if you owning one of the regions 'house_x' you can open gates leading to region 'plot' (Screenshot big red circle).
While you have not bought region you can not open gates/doors, place blocks etc. When you own house you can place blocks/open doors.
I know that you can make parent and child relations, but in my case you can not set multiple parents to one child, to pass owner (tho even if it would be possible, you inherit all the flags including building blocks in region 'plot' where you should only be allowed to open doors)