No this isn't necessary, you just need the same Selection Min viewstate
for both charts and same Selection Max viewstate. I've attached a demo
here with both the x-axis and y-axis viewstates set
The zoom can be set by assigning the same viewstates to both charts on
the Y-Axis > Range > Selection Min and Max properties. For hovering,
this can be set in Basics > Hover by assigning both charts the same
viewstate, but it follows the x-axis rathe...
