Apple limits the number of Accessories a Thinka can control to 150.
However an accessories can be a lamp that has 4 lightbulbs, that can be switched and dimmed.
In this case, one accessory (the lamp) has 4 services (the bulbs) that have 4 group addresses (on/off set and listen, dim set and listen).
So in this case 1 accessory can have 1 * 4 * 4 = 16 group addresses. So the limit of 150 accessories in practice means you can have a multitude of group addresses.
It just depends on how you define an accessory.