saved search join

Hello Gurus,

I have created a transaction saved search with criteria : type=Purchase order.

I am trying to burrow back to identify if our customer invoice has been paid before we pay our vendor bill fore related items.

i have been able to get all the related transactions to display, but in order to make this search result valuable, I  need to display just one more field on the search... the status of the customer invoice.

The invoice internalid is: {appliedtotransaction.billingtransaction.id}

Are you able to advise how i can show the invoice status on this saved search?

Thank you in advance for your help