AgreedMaybe it's an idea to just thank them there rather than rub the selectivity into the uninformed masses. The AVZ fiasco is enough of a mental hassle for long suffering holders to deal when just researching the publicly available information, let alone when you have to wonder what's being kept close-hold. Understand the reasoning for closed groups, but no need keep hinting of their existence to the rest.
A thank you out of nowhere, just thank privately or in the same channel.