SCOM URL probe datasource for URL monitoring

Hi All,

We are using SCOM web transaction monitoring and have a requirement as below.
1. if URL status code , or error code , or the URL reachability failed 2 times in a row only then send an alert.

Can you please point how to achieve this using inbuilt web transaction URL probe module.
I found that there are two variable to be used.

a) retry count
b) requesttimeout

Not sure how to use them to achieve (1).

Thanks

Manish