I have done come experimenting with subparts. I started it for a DPDT relay, so the switch contacts and coil could be moved separately.
I saw a post that said the problem mixing sub-parts and buses has been fixed, but I have not tested it.
You “may” not need a bus to do this. There is only one physical pin that is common to all of the resistors in the SIP package. So in theory you could do this as 9 sub parts. One for each resistor, and one for the common. Not sure what a ‘single ended’ resistor would look and act like in a schematic though. To do this with bus plus sub part, you could create duplicate common pins that are bused together, then implement as 8 sub parts. In breadboard and pcb, the duplicate pins can be suppressed, or stacked on top of each other. Assuming the bus + subpart problem has been fixed.
I do not think parts editor has any way to work with sub-parts, so implementing would require manual editing of the fzp file to add the subpart section. See “Split schematic symbols” in the 2.1 Part file format article for the details. That is all I used as a reference. At a high level, it is not complicated. Each separate movable piece in the schematic is wrapped in a group (sometimes called layer) in the svg file, then each piece gets a matching block in the schematic-subparts section of the fzp. That id of the block matches the id in the svg, and it contains a list of all of the connectors that are to be included in the piece. That’s it.
The svg template in the referenced article is misleading. The subpart groups should not be nested inside of each other. This should be closer: