MissAdventure, GrannyGravy13, I did not state that it was a "works WhatsApp group." It was a "private friends WhatsApp group which I am not even a member of and therefore would be unable to feed anything into them even using my WhatsApp name
To understand what can be brought about you need to understand how two or more Android phones that operate on Andriod version 8.0 and above can be linked. It can be used with several manufacturers versions of Google Android phones but not all.
The practice is typically engaged for phones used for work so collaboration on documents, picking up texts, emails or even calls to others in a linked group and can be brought about just between a number of phone/group users
That practice is widespread these days, and I never think twice about it, but I can see how the practice could cause concern to those not conversant with such technology, and I apologise if that was the case on this occasion.
However, as stated I am not alone in using the above technology and anyone having a linked phone in a workplace or household could have the same arrangement with colleagues or family. The phones can be unlinked, but like many, I never think to do that, if you have nothing to hide why would you?
Of course, the technology cannot access banking apps etc unless allowed to do so. You also have to be within a limited distance of a linked group phone for the technology to work.