Mail merge and sepertor page

[bgobank]

I am trying to insert a separator page when a field value changes in a mail merge. After the mail merge I need a macro to be able to cycle through each page, check the field value, if it has changed, select a different tray in the printer so that a colored page separates the different groups, then select the original tray and print the next group of letters and so on. The letters are all in one word document.