Get selected value from other filter

I am trying to create a custom visual which is kind of like a shopping cart. There will be a button on this visual A and when it's clicked, the currently selected item in other visuals B will be put into the A visual as a list. The user thus can export all the picked up item in A as csv for futhur data processing.

I am wondering if it's possible to intercept the selected item or the selected filters in the code? Thanks.