Hello Rafi,
Where do you specify the condition, selection screen or in the ALV output display ?
Incase of selection screen you can filter the final internal table before passing it to function module for ALV display.
Incase if the condition is specified in the ALV output, use ALV EDIT to do it.
Refer to the demo programs (BDCALV_EDIT*) available in package SLIS.
Regards,
Thanga