Linking custom fields

I’m trying to link a custom field to another custom field.

I have seen several topic’s about this but I have not found a solution yet.

My intention is to have the suppliers bankaccount number in the list of purchase invoices to create a quick list for making payments.

I would set a standard link in form defaults and it would adapt to the right number when the number is changed in the suppliers custom field.

The importance of the link is that when there is a change in a account number it just needs 1 change and you are sure to use the correct one or am I wrong here?

This is just one simple example but I believe it offers a lot of possibilities.

This is what custom reports are meant to do.

But currently, custom reports do not contain a table of purchases invoices with amounts so it’s not possible to get a list of unpaid invoices. Once this table is added, pulling bank details of suppliers into the report would be trivial.