Hate to be the bearer of bad news, but…
This looks like a great way to corrupt a model. It uses a known bug to circumvent the intended structure of groups (all workset info is stored at the host level, not the element level), where grouped content is placed in the active workset when created in group edit mode. Effectively only the first instance will get the dual workset group, and all future group instances will revert to the group’s host. Not sure if/how the existing secondary instances work here.
You may see the mix maintained long term without issue, or it could revert back to that of the group instance after something like an open with audit command, or it could go corrupt and you’ll be down and unable to open your project.
Generally speaking groups in groups are a last resort as their transforms and parameter values get overly complex, so I recommend not doing it and sticking to only single level group instances.