C# :: How To Get AI To Look For Specific Buttons

Basically I am creating a game and I need the ai to look for specific buttons. At the moment this is the code I have, and what it does is it makes the ai look for any random button that has't already been clicked.

Code:

private Button look_for_spaces() {
Console.WriteLine("Looking for spaces");
Button b = null;
foreach (Control c in Controls) {
b = c as Button; // performs a cast

[Code] .....

Now what I'm trying to do is make the ai go through 4 searches in steps instead of looking for any button. I want it first to look for buttons 1, 2 and 3, if there's a space in any then it will be clicked but if all of them are already clicked it will look for spaces in buttons 4, 5 and 6 and so on if that makes sense. But i'm not too sure how I would do it.