This is a second hand design, meaning I did not originally design it, but I'm working it now. I did not establish the disorder I am trying to resolve.
Reference SWx 2018 Premium SP2.
I have a shipping container as a building. Inside of it are chemical feed systems as subassemblies, with supply and vent flange connections penetrating the wall. Each chemical system discharges into a common water header inside the building, for dosing and treatment purposes. The water header, coming from the water booster system and passing each other chemical system before exiting the building, is in the parent assembly. Where each subsystem connects to the water header, there are fittings and hardware to complete that connection. For example, a flange pair, reducer insert, and a tee. Specifics are for context, and generally unimportant to the meat of my broader question.
I would like to be able to select two components, the header pipe and tee, in the parent assembly, and create an envelope copy into the subassembly for reference in the drawings of each subassembly. This way, it is included for reference in views, does not increase either weight or BOM quantity, and does not require the entire large assembly by configuration to be included in the isolated drawing of the subassembly.
* That is, I know that I can make a selective configuration or display state in the larger assembly. I am trying to avoid using the large assembly in the context of expressing only the subassembly.
* I could also completely destroy the item in the parent assembly and recreate it in the subassembly (Move), altering the components left behind to adapt.
* I have been measuring placement and recreating envelope objects into the subassemblies, without relation to the parent assembly. This allows the subassembly to be handled independently, but also would require manual adjustment if the header repositioned. I believe that it will not reposition, because it's already pinched into place as a driving and unifying design constraint. If it does move, I'll bite the bullet and adjust the unrelated representation.
None of these alternatives address my question directly. I have multiple potential workarounds. Instead, I ask if this is possible as stated above in bold.
Is there any easy way to do this? It sounds intuitive enough.