I'm in a LAN with Linux and Windows users. We use KNotes (KDE application) in Linux and ATNotes in Windows, discontinued in 2006. Both applications let us to send notes across our LAN (without servers) but with some issues (UTF8 not supported but ATNotes). Users only need to have KNotes/ ATNotes open to receive a note from a teammate.
As Joplin is multi-platform we would like to use it instead KNotes/ATNotes, but we need this feature as our first priority. I didn't find any plugin that implements this functionality. So, please, could you consider to add this one.
Regards and good job!!!!