Can I buy shipments of materials off settlement stores in Fallout 4?

I've got a number of settlements in Fallout 4 with "marketplaces" where I've built a number of stores. One of them has one of each "Emporium" - that is the highest level store.

Some NPC merchants sell shipments of materials.

I'd assumed "Emporiums" would sell shipments of materials but this doesn't seem to be the case.

Is it possible to buy shipments of material from settlement stores, or can you only buy them from the NPC merchants?

Are there any other ways of buying shipments in settlements?

I know that Trashcan Carla sells (useful) shipments in Sanctuary Hills and Connie Abernathy sells (less useful) shipments in Abernathy Farm. I've seen references to setting up a caravan from Bunker Hill but I haven't worked out how to do that yet.

Solution 1:

Can't prove a negative, but I've never seen any shipments from the vendors that I build. I've stocked several with tier 4 general store vendors and they still don't have any shipments of materials.

As for Bunker Hill, it becomes a possible settlement point after a certain quest:

The Battle for Bunker Hill

And there are shopkeepers there that sells some shipment items. It seems to be the only possible permanent way of purchasing shipments while on a settlement.

Update:

There are a few other possible settlements with a npc vendor that sells some shipments:

Abernathy farm and covenant. However for covenant, you need to:

Side with Dr Chambers in order to not have to kill the town.