I can easily use SUMIF() to get totals based on the contents of cells in a column, but is there any way to do the same to add up, for example, only the cells that include the character "I" (or any other character) anywhere in the string?

e.g.
817001 - I - 16/07/14 (include this)
3567777 23/6/14 (exclude this)
235555 I 22/7/14 (include this)

I know I can use the FIND function to look at each cell, but this would mean adding in an extra column to store the answer I need to use for the adding up. It's not my file and is live so I don't want to do that.

Any ideas? Thanks.