>I need the ability of the user to specify that a particular report will always be
>sent to a certain printer without the user having to select it every time the
>report is printed.

Create a form that links reports to printers. Before you run each report, access that table and set it to the indicated printer. Use the APRINTERS() function to make sure the printer they've setup on that form still exists in context on the local user's machine.

>For example, all invoices will be sent to a pre-selected printer disregarding
>any default printer settings at the workstation where the report was printed.

Yup. That'll do it.