Réponse acceptée !
Exemple:
#define DEF WS_CHILD|WS_VISIBLE|BS_AUTORADIOBUTTON
// premier groupe
CreateWindow("button", "but1 group1", DEF, 5, 5, 50, 20, hWnd, 0, 0, 0);
CreateWindow("button", "but2 group1", DEF, 5, 25, 50, 20, hWnd, 0, 0, 0);
CreateWindow("button", "but3 group1", DEF, 5, 45, 50, 20, hWnd, 0, 0, 0);
//second groupe
CreateWindow("button", "but1 group2", WS_GROUP|DEF, 5, 65, 50, 20, hWnd, 0, 0, 0);
CreateWindow("button", "but2 group2", DEF, 5, 85, 50, 20, hWnd, 0, 0, 0);
CreateWindow("button", "but3 group2", DEF, 5, 105, 50, 20, hWnd, 0, 0, 0);
Je n'est pas testé mais je crois que c'est bon.
C++ (@++)