In ACRO there are only two curves. Looking up your ESC on the web, I see why you are asking about more than two throttle curves. Using a throttle curve to disarm or kill the ESC on the 11X is in my opinion hazardous. There are better premixes on the transmitter to do that. Using a throttle curve for that purpose is not sure fire if the throttle trim is left active. So what you may need are three curves at most.
You can create a third curve by using a curve program mix. This will require a bit of work to make the third curve act the same as the two other curves if the throttle trim is not inhibited.
Allan