BOM for a purchased component?


Here's my issue. We have a part that is made by a sister company (set up as its own branch plant). Now, we are purchasing the raw material for them through our system. What I am trying to do is set up the items/BOMs such that:

1. A work order is generated for the assembly, with the sister company's component in the BOM/parts list.
2. Running MRP on the sister company's component changes the planned PO's into actual PO's.
3. When a PO is issued for the sister company's component, a second PO is generated for the raw material they will need to make their component.
4. We'd do receipts for both the raw material and the sister company's component.

I've got 1 & 2 working. But I'm getting stumped on the PO for the purchased sister company's component generating a second PO for the raw material. I've tried setting up as a standard BOM, with the sister company's component being level one and the raw material being level 2. I've also set the Stocking Type Code on the Item Master for the raw material as "0" for phantom. I don't see any place to set up the BOM as a phantom BOM. I have NOT set up a routing for this BOM. I have for the main assembly.

Am I trying to accomplish the impossible? I'm not familiar at all with phantom items or phantom bills, but my reading through other posts and JDE materials led me to believe this might be the solution. If it is, I haven't figured what it is.

Any help would be greatly appreciated!