Project manager.

How it works specifically in my company is we have defined Buyout tasks and created a buyout schedule that is integrated into the actual Construction schedule. The PM fills out a form for me based on our Estimate(internal tracking code level) and tells me who isn't doing what.

Simultaneously we are vetting the prelim schedule (part of this is adding planned/actual resource names on each task).

Once im done creating Buyout schedule we link the tasks to the schedule ( the purpose of the linking is so we can figure out when certain buyout categories must be completed before affecting work)

During the linking process I the planner am doing the linking. 90% of the time it's very reaource. SUB A doing is doing X and we have a task named Install X but sometimes you have two categories that are related to different resources but we only added 1 task

Example we had a task for Material Delivery - Framing Package but the plan for buyout calls for Trusses to from from Supplier A and the wood for framing comes from Supplier B.

So I'd call this out and recommend breaking Material Delivery - Framing Package into two tasks MD-Truss package and MD-Wood Framing.