The second of each event won't trigger though. You can only have one event in each file for the same event.

on ^*:JOIN:#:{
if ($nick == N9NU-|-Linux) || ($nick == N9NU-|-HamPC) haltdef
}

OR

on ^*:JOIN:#:IF (N9NU-|-* iswm $nick) haltdef

OR

on ^*:JOIN:#:IF ($fulladdress isignore) haltdef