Basic code
Code:
on *:start:{
.server network1 -j #chan1,#chan2,#chan3
.server -m network2 -j #chan4,#chan5,#chan6
}

Replace network1 and netowrk2 with the actual network name/address
Also replace #chan1 (etc) with the actual channel names.

NOTE: if the channel requires a key for entry, this code will require editing.

To add additional networks, copy the format of the second .server line