Allow linking of items ie expense and refund

• A airline booking can be a receipt and a document

• A expense can have a refund later

• Two or more receipts might belong together.

• A bank statement is linked to many receipts

• One receipt is linked to one bank statement

In all those cases and more its helpful if entries can be linked to each other

Often it can be manual and in the case of a bank statement automatic

It could just show up in the UI as a link field ie #R343 or #D232 and then when the user clicks on it they are taken to the related receipt

the unique number feature request could fit in here