Hi,
You can't use global binding as that only works with the value of the drop down, not the actual list. You can use a predicate binding, so if I had some xml like
<Languages>
<currentLanguage>1</currentLanguage>
<Language id="1" display="English"/>
<Language id="2" display="French"/>
<Language id="3" display="Maori"/>
<Words>
<Word language="1" id="1">one</Word>
<Word language="1" id="2">two</Word>
<Word language="1" id="3">three</Word>
<Word language="1" id="4">four</Word>
<Word language="2" id="1">un</Word>
<Word language="2" id="2">deux</Word>
<Word language="2" id="3">trois</Word>
<Word language="2" id="4">quatre</Word>
<Word language="3" id="1">tahi</Word>
<Word language="3" id="2">rua</Word>
<Word language="3" id="3">toru</Word>
<Word language="3" id="4">whā</Word>
</Words>
</Languages>
The first dropdowns list is bound to the Language element with $record.Language[*] and the value of the dropdown bound to $data.Languages.currentLanguage.value, the dependent dropdowns could be bound to the appropriate Word elements with $data.Languages.Words.Word.[language == $data.Languages.currentLanguage.value].
This way the only actual code you will need is a xfa.form.remerge() in the exit event of the language drop down. Using remerge() will mean any form properties that have been updated by script will have to be re-applied. This tends to be things like error highlighting or calculated values that are not bound to the data connection.
I have a sample of this approach here, https://workspaces.acrobat.com/?d=JEiwbw2GgRngqwL8umw8Og and some xml to preview it here https://workspaces.acrobat.com/?d=nXh795dIs8DLJ2erx5j1QA
Regards
Bruce