I have the following sample data:

key | source_string
---------------------
1355 | hb;am;dr;cc;
3245 | am;xa;sp;cc;
9831 | dr;hb;am;ei;

What I need to do:

Find strings from a fixed list ('hb','am','dr' ,'ac') in the source_string
Create 3 new attributes and assign the found strings to them randomly but fixed (no difference...