Found myself the solution: -set the no data source options to "all selections, no detail" -Create a column header band with a new field " " (meaning an empty field) -Set the header band "print when expression" to "$F{subreportValue} == null So if there are values, the column headers are not printed and only the values are shown If there are no values the column header band with 4 empty cells is shown in the mainreport, therefore the cells aren't merged
