If I understand your question correctly, then you want you to be able to specify the subnet mask in your blacklist, like: "
170.158.*" and use that to intercept suitable IP addresses that connecting to your network?
Before helping, I need to know what the echo response will be if you install a piece of code like this:
on *:SNOTICE:*Client connecting*:{
/echo -s $1-
}
This is because this value is different on different IRCd servers.