CRM 4.0 Workflow OR conditions

I need to create a workflow that has multiple OR conditions. The Check Condition allows And only. What is the best approach to accommodate an OR scenario?

Scenario:
Business has identified 13 fields that must be populated before moving to next step of process.
If one or more of the 13 fields are not populated, send email XXX
Otherwise if all 13 fields are populated, send email to XXX