Thanks - have been doing some searching
GenBox has the function - not sure I like how it treats 2nd / 3rd marriages, but it may be able to be customised
Family History Maker's Extended Family Tree may mean the same. But they don't have a trial version and I'm not prepared to pay A$60 without seeing it first.
wintree 5.0 - is a free option, but it doesn't allow GEDCOM data to be imported
Legacy - definitely not
will try Family Historian