Unifying by joining in the app, but I also used an indirect way of getting it on the same network (using the help of a smart device that I add to the samsung BR) and then from there I can get Home Assistants Hub into it which is followed by everything else. So I basically have to do a mix of methods, and currently everything is on the ST-Dongles network,
the Hub Group sharing credentials would still leave the same issue with the dongle unfortunately 
which is why i was hoping it’d be possible to either be able to add the dongle to the group, as a secondary BR or relay booster or whatever… and then I move the rest into that group using my indirect way…Or to move the Hub Group into another network while keeping the connection between the two hubs active, just the rest of the stuff lines up with the main network instead of the primary hubs network
I used to have the station and Hubv3 in a hub group and then put everything into that Hub Groups network using the same indirect method. Except that way doesn’t allow me to move the ST-Dongle BR into it, as the dongle doesn’t allow for changes to it.
I dont see any hub that accepts shared credentials, nor can I get dongle to share or accept any
Unifying the Thread network with all the other 3rd party BRs is not possible because in a hub group the only thing you can do is share “out” and none of the 3rd parties listed don’t seem to have support for accepting the credentials to apply to their own BRs.
So is there no way to do anything with the dongle after I get the other hubs into the one created by the hub group? Sounds like by design the hub group is not allowed to move into a third network without the two hubs splitting apart. Does that mean the dongle just wasted/destined for the trashcan then?
https://community.smartthings.com/t/role-of-a-st-dongle-if-it-cannot-be-part-of-a-hub-group/ - For further context
Also by reset I meant the linked thread network that comes out of the grouping ends up reverting to the old name (that was default for the primary hub of that group) rather than newly set name from the network that they were both already in prior to grouping.