I've been thinking about a WLAN for every group/network by using a Software Access Point
https://wiki.archlinux.org/title/Software_access_point
So it can uses arleady existing wireless devices and networks, and every user can localhost on it by his linux device
-the network don't need to be always running, less than a minute every hour could be more than enough
-wearable wireless devices can make the network more flexible
I'm not talking about Linux-phones but something cheaper like linux-smartwatch or even earplugs, everything that's wireless and easy to hack
When back home you only need to wait for it to run the WLAN again for all your home desktop devices to be SYNC, and even post something that someone else will read tomorrow or the day after