@pmario Thanks. And it worked perfectly. I polished it a bit with:
<$vars last={{{ [<currentTiddler>get[related]enlist-input[]last[]] }}}>
<$list filter="[enlist{!!related}]">
<$link />
<$text text={{{ [<currentTiddler>!match<last>then[, ]] }}}/>
</$list>
</$vars>
to remove the ‘,’ after the last item.
The code is not my own. I picked it up from an answer to another question here.