Sample code of start routine filter out unwanted data by field value

Hi, Experts:

We are using BW3.5. I need to run delta load from an ODS1 to another ODS2 or Cube2 with only selected data. The unwanted data will be idetified by a field ITEMCATEG with values in a exclude list like ("ABC", "DEF"...).

In the infopackage, the selection tab is blank. Reading from other posting, selection does not seem to be possible for delta load from a ODS source. Is it right?

If can't select from infopackage, I am thinking of using start routine to load only selected data. But I am not good at ABAP coding. Can someone please kindly provide me a sample code of start routine that can filter out unwanted data by a value of a field?

Many thanks!

Jenny