With some tinkering around in Tables and Cos menu I might have figured it out. Image instructions follow:
Start:
1. Tables / Split
2. With A, B and C columns selected go to Cols / Utilities / Combine Columns(might want to keep Multiple Response, depending how you use the data)
3. Delete unnecessary colums A, B, C
4. To go back, select Market column and go to Cols / Utilities / Text To Columns
5. Tables / Stack
6. Delete Label column
-Jarmo