I haven't played with mixing the modes yet but if anyone has any ideas, I'm always keen to learn something new

/help /join
u can set it at format /join #chan1,#chan2,#chan3,#chanN
so no need to loop just place # at the begin and replace the "," by ",#" and remove all spaces and if some chan has # u replace the ## bye #

alias j join $remove($+($chr(35),$replace($1-,$chr(44),$+($chr(44),$chr(35)),$str($chr(35),2),$chr(35))),$chr(32))

u can use /j chan1,#chan2,#chan3,chan4,chan5 ,chan6 , #chan7 so all case