For Georgia and South Carolina it should work as I described above. You include the gain from the sale on both state tax returns. On your Georgia tax return you will get a credit for part or all of the tax that you pay to South Carolina. Prepare your South Carolina nonresident tax return first, then your Georgia resident tax return, so it can calculate the credit. I'm not familiar with these particular states, but at some point in the South Carolina interview it will ask you to identify what parts of your income are from South Carolina.
