Average formula

[Pojzon]

Hi. I'm having trouble with setting average formula. I would like it to check for string ex. "Test" then sumup every row(C:W) where It is found and do average of this excluding empty cells. Same with Test2, Test3 etc. Subtotal works perfectly fine when filtered, but I would like it to work also when filter is off. Is that possible? I'm using excel 2010.