u can refill it with all the nicks using a loop
alias filllist {
%sn = 1
did -ra $dname 1 $nick($chan($active),%sn,a)
%sn = 2
while ( $nick($chan($active),%sn,a) != $null ) {
did -a $dname 1 $nick($chan($active),%sn,a)
inc %sn
}
}

may not apply perfectly to your need but im sure u can tweak it a bit .. and on certain events u cant then refresh your list of nicks from a channel . hope this gives u any insight into what your looking for