Here's one thing you may be asking - do you want to know how to specify a join for n sources? If so, maybe this example will help:
declare variable $eng := (<d n="1">one</d>, <d n="2">two</d>, <d n="3">three</d>, <d n="4">four</d>);
declare variable $deu := (<d n="1">eins</d>, <d n="2">zwei</d>, <d n="3">drei</d>, <d n="4">vier</d>);
declare variable $ukr := (<d n="1">один</d>, <d n="2">два</d>, <d n="3">три</d>, <d n="4">чотири</d>);
declare variable $heb := (<d n="1">אחד</d>, <d n="2">שתיים</d>, <d n="3">שלוש</d>, <d n="4">ארבע</d>);
for $e in $eng
for $d in $deu
for $u in $ukr
for $h in $heb
where $e/@n = $d/@n
and $e/@n = $u/@n
and $e/@n = $h/@n
return
<wf>{ $e, $d, $u, $h }</wf>