How to add multiple assertions in soapui load test

Hi All,

i have to add multiple assertions in the loadtest.. eg: i'm adding step maximum assertion to validate my respone time of my webservice. so i need to specify 1 assertion for 350 ms respnse time and second assertion for 450. so when i ran that loadtest. i'm calculating the % of response more time than 350 if i have 1 assertion.. count/err*100. so here in the load log i get entries exceed the response time 350 and 450. so how can i get individual percentage report. Thanks