How to add custom lookup-type field to meeting module form in Zoho CRM

We need to have a lookup field to a custom module's record in Zoho CRM. But it appears that look-up fields are not enabled in Meetings/Events module in Zoho CRM.

How do I design/implement a custom look-up type field that will lookup records from custom module and enable users select and store the selected record in Meeting record and asscoiate/create a related record in the meeting record? Similarly and more importantly, the event/meeting record will be stored as related record in the custom module - record just like it is stored and associated for Contacts.

Moderation update: This can be done today using the standard "Related To" field. Set it to Others and look up the record from your custom module. Since Related To holds a single record, this works if you need one lookup. Support for custom lookup fields on the Meetings module is in the pipeline for anyone needing more than one.