A Portal to Sources will list all related sources records for the given contact, but you should rethink using last names as the match field in the relationship. What will you do if you get two contacts named "Smith"? What will you do when Mary Jones changes her name to Mary Smith? Or you find out after the fact that Jim Smith is really Jim Smythe?
I suggest defining an auto-entered serial number in contacts and using it to link to records in your sources table.
PS. in your script, if you remove the Go to Related Records step, you'll still get the same results.