Record count since last occurrence - Crystal 2013

Hello Everyone.

I am trying to work out how to best calculate this. I have some records in my details section which is grouped by name.

Group = Name of Runner (John Smith)

I am trying to return how many '0' occurred before a win was reached. For example Johns last 3 races he did not win, so i want the value to show in the group footer as "3".

I am also then trying to only look at the last 10 records in the detail section. if john has not won in the last 10 records then i want it to show "10"

any ideas?

thanks everyone