There is no subheader feature in ALV for SAP GUI. This has been discussed many many times in the forum. The only way to mimic it is either to use different colors for columns, and some people like to define the first line for storing header texts (I find this solution horrible). It's not possible to merge cells horizontally too.
Even with ALV for Web Dynpro, the solution of using line feed in the header is not satisfying according to me.
See the good answer by Clemens Li
You may also change the way of displaying elements, like defining 3 ALV grids (one per type of data), with a tabstrip to select which ALV to display.
Otherwise, colors, definitely.