ALV TREE

Hi Experts,

I am working on the ALV TREE. I need three folders to display data upto four levels , like first one for Available Flights, within it the next one for Schedule, And within it for Flight Times and this will display all the times. Now I am able to display folders up to two level but on third level I am getting the records but not the folder icon to hide the next level data.

Can any body help me how I can do that.

Thanks in advance