Create a new branch type to replace optional canoverride (spawns only after all other branches are down spawning). Treat optional canoverride branches like other branches (spawn in the same cyle). At the moment, you can't chain optional canoverride branches, you can only use them once, to create 2 phases (1: Structure fundament/layout, 2: randomised interiors/modifications), Allow the new branch to chain, so that users can add as many phases as they like (structure fundament, walls, roads, structures, interiors fe). This will create problems for collision detection, so add a collision-group setting, like Branchgroup/BO3Group, that allows users to group structures that can collide with each other.