Custom multi-lookup field not available as an option in the Business Card view

Custom multi-lookup field not available as an option in the Business Card view

Hello! A custom field "Subsidiaries" is not showing up as an option to add to the business card layout.  We have only four of the five fields selected, and other custom fields are available.  "Subsidiaries" is a multi-lookup field and the only one we have. It is showing up on the account module as a field in the section below the business card.