A structure, such as a pillar, that when placed in a location will demarcate a square area of a certain number of foundations around that structure. Such a structure in 3 or more models, where each model will guarantee a specific square area around itself.
Example:
1 - Golden Master Demarcation structure - guarantees an square area of 40x40 around it.
2 - Silver Master Demarcation structure - guarantees an square area of 25x25 around it.
3 - Bronze ... ... ... ... ... ... - guarantees an square area of 10x10 around it.
That means: when this structure is placed, in that area anyone cannot place structure in that, unless you and your tribe. Maximum of 2 master demarcation structure per tribe.
Inside this area, your decay time od structure will be the same we have now. Out of it, will be something like 2 days. The idea is to vanish that pillar spam.