Dynamic IP Restriction message for user

I have installed/enabled/set up Dynamic IP restrictions, including limiting the number of concurrent connections for a given IP address. I have looked all over the place and cannot figure how I can create a custom message that a user will see if this condition exists when they try to access the site.

Is there a way to create a feedback message for a human user?

Edit

I found this error code 503.2 - Concurrent request limit exceeded at this Microsoft support site. Is this the matching error message for the concurrent IP restriction? 

If possible, I would like to customize/humanize the error response if it is the right one.

Thanks...