Using Joined Search Field Values
You can use values from related records in your search criteria and results by adding joined search fields in your formula definitions. Specify joined search fields with dot notation: {record.field}, where you enter the related record first, and then the field. For example, to include the credit limit from a vendor record associated with a contact, use {vendor.creditlimit}.
Note:
You can select a field to include in a formula expression using the Field dropdown list in the Formula popup window. Joined fields appear at the end of the dropdown list. When you select a field from these lists, the system automatically enters the correct ID in the formula.