Re: create custom field such as Organization or Work group
If I understand correctly, you want to create an Entity Reference custom field. To create such fields you need to either activate them from the Administrator Console: Data > Custom Fields > [Entity] > Entity Reference.
Or, you if you're using SP18 or higher, you can use Unlimited Custom fields if you've already used the out-of-the-box custom fields.
The underlying logic used by quick find is hard-coded.