Join on custom fields

Summary

Can we join Incident and Contact when we have a custom field which acts as common key

Content

Hi All,

Instead of using standard join Incident.c_id = Contact.c_id, can we join them on a custom field, for example Inciden.c$customField = Contact.c$customField where customField's value on incident is a copy of that of Contact?

Regards,
Hanu.