On your subscriptions page https://status.vinilox.eu/vinilox/subscriptions for each #micro user click on the "tag" icon (supposed to look like a pencil) and type in "microuser". When all the right users have been tagged you can address them all with @#microusers Think of it as a distribution list for !GNUsocial Instructions are at https://status.vinilox.eu/doc/tags under the "Tagging others" section.