You need to include those fields as ‘query_only’ in the subpanel definitions.
For example, if the module is Contacts, you would have those definitions in
custom/modules/Contacts/metadata/subpanels/some_name.php
and fields can either be an actual part of the subpanel (showing as columns) or ‘query_only’ meaning you need to use them but not show them.
Here’s a segment of an example file with one field as ‘query_only’:
$subpanel_layout['list_fields'] = array (
'first_name' =>
array (
'name'=>'first_name'
'usage' => 'query_only',
),
'photo' =>
array (
'name' => 'photo',
'vname' => 'LBL_PHOTO',
'width' => '5%',
'default' => true,
),
Also, check out the customCode in this same file, it let’s you easily put together field values.