ASM Policy in "Blocking" Mode switch to "Transparent" for some IP's

Truthfully I'm not sure this use case occurred to the team that developed the ASM. The ASM is designed to be used in transparent, then moved to blocking. Because the transparent/blocking setting is a setting that is global for the entire policy, it can't be easily toggled on and off per connection.

ASM can be disable for certain flows very easily, as we simply pass the request to the back end servers without handing it off to bd (the ASM process). Setting ASM to transparent for certain IPs would be far less straightforward (and is likely why irules can't do it). You might be able to convince PD to whip something up to do this, but likely not without paying for the feature (an expensive proposition, but your Account team can help).

Barring that, duplicate policies will be your best option.