How to reference elements in a DC Component?

[derei]

I'm working on a DC component that have several elements which must interact. If I click one, it must rotate, but in the same time, other one must hide.
How to reference them, to pass a variable value from one to another? from parent to child is easy, I just use =parent!attr_name, but how to pass a value up, from child to parent? Or between two components of same level?

Thank you.

EDIT
I moved the variable in the top (parent) component and I referenced it down... but this seems to slow the rotating animation A LOT, it's a simple component that needs to be rotated, but it happens jerky, instead of smooth move! This is why I would like to pass the value upwards.
Actually I could reference using component_name!parameter_name , but is not updating. Te parent's variable gets the initial value from the child, then it doesn't update anymore.
Any thoughts?