Payroll segment defaulting for SLA

Summary:

I'm trying to set a default segment value for payroll SLA when a value is NULL/Blank in payroll subledger so I can create accounting. If the value exists, I would want to pull the source value.

Content (please ensure you mask any confidential information):

I am receiving a create accounting error from payroll because the subledger accounting does not have one of the accounting segments populated. Is there a way to set an IF statement in SLA to say, "If Source value exists, then Source value, else default 'xxxx'?

Version (include the version you are using, if applicable):