Forms are "locked" to a particular printer, unless you untick "Suppress Print Dialog" under Form Properties for the form. Then when the form is printed, the user will be presented with a print dialog and can select what printer they want to send it to, at that point.
Things are more complex if you want user A to always print to Printer 1 and user B to always print to Printer 2 (without pausing to ask which printer to send the form to). If this is what you want to achieve then you can:
1. Create a different form for each user. If you do this do not specify the default form under Install|Forms... leave the form names blank so that users can save their own forms based on the last ones they selected. The problem with this approach is that if you change a form you need to make sure that all other forms are also updated.
2. Install the printer twice and rename the second driver to "CAPITAL Invoice Printer", etc. Save the form to this printer name. Then repeat this for each user on the network. That way users can have a default printer, a single form, but have the data sent to different printers on different stations.
Just be careful that if you do (2) you make sure the form is small enough to fit on all printers correctly, as under Windows the margins, and page size vary from printer to printer, even if you select "A4" size paper. Form printing is not like printing doc's or spreadsheets that just wrap if something doesn't fit on the page. With forms you have to fit everything on a single page.