Hello,
What version of BIG-IP do you use?
You can use L7 policy for this purpose "Local Traffic ›› Policies : Policy List".
You need to create L7 policy with 3 rules with different ASM policy each and assign this L7 policy to your VS via "Policies" in "Resources" tab for VS.
AFAIU, in your case you need to use next rules:
- HTTP URI pass start with "appserver/app1" -> Enable asm policy1
- HTTP URI pass start with "appserver/app2" -> Enable asm policy2
- HTTP URI pass start with "appserver/app3" -> Enable asm policy3
- All traffic -> disable asm
Thanks, Ivan