Help Question about garment onto a 3d avatar using Obi

[onfitpark]

Hi,
thanks for your advice.

I'd like to share another question regarding physical matters while the body mesh is wearing a top and a bottom.

I set each clothes to have each ObiSolvers, gave them the same value. After simulating it, they didn't collide each other.
On the other hand, with one parent ObiSolver and two children, they look good; seems like they did collide each other. The top located on the outer layer as I intended,  and didn't pass through the bottom or the body.
In hierarchy-wise, I was wondering if there's certain principle in it. And I wonder which one is more stable.

Also, I was wondering if there's a way to designate a child that it should be placed the outer/inner layer.

Thank you