You can use "within" option with "trigger". For example if your rpm executed once in 1 min , so you need to check if rpm was succesful 15 times
We configured this some time ago
services { rpm { probe script { test src1 { probe-type icmp-ping; target address 10.7.0.1; probe-count 1; probe-interval 1; test-interval 1; source-address 10.7.0.2; } } event-options { policy ping-fail-src1 { events ping_probe_failed; within 32 { trigger on 15; } attributes-match { ping_probe_failed.test-owner matches .*script.*; ping_probe_failed.test-name matches .*src1.*; } then { event-script change-nexthop.slax { arguments { nexthop-address 10.7.0.1; metric 20; } } } } policy ping-success-src1 { events ping_test_completed; within 31 { trigger on 15; events ping_test_completed; } attributes-match { ping_test_completed.test-owner matches .*script.*; ping_test_completed.test-name matches .*src1.*; } then { event-script change-nexthop.slax { arguments { nexthop-address 10.7.0.1; metric 10; } } } } }