Lee,
it’s very simple and doesn’t require any adjustment to your code. Here’s how:
(1) In AmiBroker set up a new watchlist and call it ExcludeList or something else.
(2) Type in any symbol(s) you wish to exclude into that watchlist.
(3) In the Filter box where you normally select the universe, use the Exclude tab at the top and use your new watchlist therein.
Now run your normal backtest and any stocks in that new watchlist will be excluded.
If you get stuck, book a call with me and we can do a TeamViewer session.