light in display for the ALV hierarchial list

Hi,

I have a requirement in which the scenario is like this,

The output of the display must have sales order number, batch, delivery number , shippment number, etc.

If the delivery is created for the particular sales order, then on the left corner, green signal has to display, if not red light.

Can any one help me out in finishing this task?

What code to be written and what events to be called in the display?

Points for useful answers.

Regards,

kumar