Code:
alias shouldstrip { if ($nick == Joe && $chan != #main) return $true }
on ^:TEXT:*:#:if ($shouldstrip) { echo -mbflirt # #+(<,$nick(#,$nick).pnick,>) $strip($1-) | haltdef }
on ^:ACTION:*:#:if ($shouldstrip) { echo $color(action) -mbflirt # * $nick(#,$nick).pnick $strip($1-) | haltdef }


Note that if you have theming scripts you have to make sure the above will echo in the same format as your theme