Filter on write back badi

Dear All ,

we are implementing  different input schedules to send data , for some of them we to use default logic because there is no logic in the BADI, for the other we want to trigger the write back badi.

what I noticed that when you choose to implement the write back BADI  all the input schedule are going through

1. is possible to combine default logic and write back in the same model , in other way I want to use default logic and other write back ?
2. is it possible to filter in the write back by input schedule , I don't like to loop over the ct_data to find the element that is coming  from specific IS ? any solution with global variable if it contains the of input schedule ?

Thanks

Mohamed Faouzi