In response to your query
on *:connect:{
.list
$+(.timer,$network) 0 1200 list
}
on *:disconnect:{
$+(.timer,$network) off
}
That will generate an initial list when you connect to the network, then update it every 20 minutes. If you want to restrict the listings, alter the list commands (there's two of them) using the options available at /help /list
This will also track multiple network connections