You can do this with a few cool tricks!! Let's assume your report has a data group on CUSTID. What you need to do is create two Data Groups .. the first one has the following expression and is marked to start on a new page:

EVALUATE(pcGroupExpr)

The second data group has CUSTID as the expression and it is NOT marked to start on a new page.

In your program that calls the report use the following code:

PRIVATE pcGroupExpr
IF <You want page breaks>
  pcGroupExpr = 'CUSTID'
ELSE
  pcGroupExpr = '""'
ENDIF

REPORT FORM MyReport TO PRINTER PROMPT PREVIEW