I'm speaking for myself now, not "management," but I think plant trading is discouraged. There are lots of laws/ regulations about what can be shipped where, which ordinary people are probably not aware of. But they are there for a reason, to try to prevent more pests from being spread around. Most often insect pests and plant diseases appear in a region carried along with plants that are shipped there.
Look for your sumac in local nurseries or reputable catalogs that are aware of the regulations and know how to do clean packing.
I have traded plants here many times. You should know if it is allowed in your state. I have this sumac you are looking for and it is very much a pain to keep under control. FYI
Live, Love and have a caring heart. Because tomorrow my be to late.