If you want the exact same thing they currently have, you just have to substitute the corresponding values in the search form: You currently have

<form action="http://www.refworks.com/refshare/?" name="rice" mode="get" onsubmit="return validateForm()">
<input name="qs" size="25" maxlength="150" value="Search research database" style="color: rgb(0, 0, 0);" onfocus="if (value == 'Search research database') {value='';style.color = '#000000'}" onblur="if (value== '') {value='Search our Research Database'; style.color = '#888'}" type="text">
<input name="site" value="010271135929600000/RWWS3A1442269/Conservation Agriculture" type="hidden">
<input name="submit" value="Search" type="submit">
</form>

If you just replace http://www.refworks.com/refshare/? by
https://www.zotero.org/groups/<group name>/items/q/ and remove the hidden input, you should get a basic title/creator/year search in the Zotero library.
To make it an "everything" search (which I'm not sure how well it works currently to be honest), you'd have to add /qmode/everything at the end of the submitted search URL. I don't know the html form code for this off the top of my head, but shouldn't be hard.

To have the entire search happen on a locally displayed version of the library would be significantly more effort, of course. You'd have to run libZotero locally (which is certainly possible, but seems to go a lot further than what you're trying to do here).

Please do let us know if that works -- I did this on the quick and obviously w/o checking, so I'd want to know if this works as desired.