OK, for command overrides, i cannot make a plugin that overrides commands (in my knowledge), but i can easely modify any comand af any plugin and make two plugins work in symbiosis.
as for the structure i thaught you use a 3x3 base with a chest in the middle for upgrade gems, and arround use stone material. if you use fire brick it gives x2 multiplier (if the structure is completely made out of it) it will then be upgraded with a pyramid like shape (image below is a tier 0 tp station)
and then you would need to upgrade it up to level
(minimum of the max tier, can be blue steel too, all blocks are firebricks and the inside is hollow, so perfect for charcoal pits
)
(with some deoration)
these are design samples, just to show a sample, give your opinion