Access to a sublayer in the stack
When you add a sublayer in the stack of a group layer, you're able to continue to modify it:
$sublayerId = 2; $group->layers[$sublayerId]->doSomething();
Sublayers of sublayers can be modified too:
$sublayer1Id = 2; $sublayer2Id = 1; $sublayer3Id = 4; $group->layers[$sublayer1Id]->layers[$sublayer2Id]->layers[$sublayer3Id]->doSomething();
Now, we will see how to merge plural sublayers in a group stack.