How about this:
LB1 = listbox influencing charts 1 & 2 (CH1 & CH2)
LB2 = listbox influencing just chart 2 (CH2)
Create a single Alternate State and assign LB2 and CH2 to that state.
Both charts will be influenced by LB1 by default as this is an object influencing everything in your application.
Or did I get it wrong?