Different response for violations

Redirection based on source IP address is best done on LTM not ASM using Local Traffic Policy or an iRule.

ASM Blocking page should really be used for genuine security policy violations, not for redirecting users to a different page.

There are lots of sample iRules on DevCentral - just search for "source ip" and "redirect". Local Traffic policy config is more or less user-friendly and the guide is available here:

https://support.f5.com/kb/en-us/products/big-ip_ltm/manuals/product/local-traffic-policies-getting-started-12-1-0/1.html