By the way, the prior message was intentional hair-splitting about what Groups.io itself does and some common parlance.
If a group has assigned moderator(s) along with owner(s) they can both generally use the #adminnotice hashtag because all are in administrative roles. Groups.io just doesn't use the title Admin or Administrator. Whether a group owner does, as James just did, is a completely different matter.
Brian - Windows 10 Pro, 64-Bit, Version 20H2, Build 19042
It is better to be hated for what you are than to be loved for what you are not.
~ André Gide