Trigger selected action on Form Saved based on condition

[stephenrich]

Dear Appsheeters,

I have a Sales Invoice Form, where I want to auto generate the item list once the form saved.

I already create two sets of actions:
Action Set 1. Copy Item List from [Sales Order Details] to [Sales Invoice Details]
Action Set 2. Copy Item List from [Sales Quotation Details] to [Sales Invoice Details]

My Question is, is it possible for me to trigger one of those two actions, based on condition, for example, if the Sales Order No. in the Sales Invoice is not empty, then trigger Action Set 1 to copy Item List from Sales Order Details to Sales Invoice Details, But If the Sales Order No is empty, and the Sales Quotation No. is not empty, then trigger Action Set 2 to copy Item List from Sales Quotation Details to Sales Invoice Details.

I cannot find where to put the expression on the event when the form saved.

Please advice.

Thank you.