In this case, I’d use SSJS to print the keyword to generate the asset listing with a dynamic root node. Something like:
<script runat="server">
print('%' + 'globals_asset_contents_raw:1234^with_get:root=' + '%asset_metadata_your-ct-metadata-field%' + '%';
</script>
Where root is the dynamic root node parameter for the Asset Listing with asset ID 1234.