code: public static boolean foundFunctionInGroupHeader(ReportLayout layout, String groupName) {
  		List<Band> groupHeaderBands = layout.getGroupHeaderBands();
  		for (Band band : groupHeaderBands) {
  			if (band.getName().equals(ReportLayout.GROUP_HEADER_BAND_NAME_PREFIX + groupName)) {				
  				return foundFunctionInBand(band);
  			}
  		}
  		return false;
  	}
docs: Test to see if a function is found in group header band
  
  @param layout report layout
  @param groupName group name
  @return true if a function is found in group header band, false otherwise