Custom Block Hitboxes (If there is a way, message me)

This is a problem for me because if I make a block that's two blocks tall and/or wide, I can only change how big the player to block detection is. In other words I can stand and walk into it but can't hit/mine/destroy the "2 wide/tall block"; it only detects 1 block still. Also the mobs can shoot through it. Let me know if there's a way to do this, I'll feel stupid if there is way lol.