Manage Process Assignment Rule and EFF

Summary:

Is it possible to call a custom orchestration using a value held within a Line Level EFF instead of having to declare an 'Order Type' condition all the time?

Content (please ensure you mask any confidential information):

I cannot seem to create an Orchestration process Assignment rule to call my custom orchestration process where the 'If' statement is something other than 'Order Type is xxxxx'. For example i would like to call a custom orchestration process if at line level a specific eff contains a value, so the 'IF' statement is if 'eff' is not Null Then run process.