Signature sets precedence for ASM Policy

Had a query on signature sets on ASM Policy. In my Policy Attack Signature Configuration, i can see multiple groups based on which i can select either to learn, alarm or block. Basically i want to tune my policies as all of the signature sets are currently on block mode. If i want to disable just the OWA Signatures and set it to Alarm only. Should i be disabling block for "All Signatures" as well and select Attack specific signatures sets. Will enabling block for "All signatures" override the "OWA signatures" Learn only setting? Wanted to know the precedence of applying signature based checks.