There isn't a perfect filter to set up what you want. But you can create reports to look at certain kinds of hands and see what you can see. First you'll want to become familiar with our Filters system though - our tutorial on the filters is
here.
Here are a couple of ideas that might work to get you some idea. You can filter for:
Saw River and Saw Showdown
vs
Saw River and NOT(Saw Showdown)
to see how often the hand ends on the river. These are tournaments so this might be rare, but it would be relevant if you had a chance to fold and were doing so some percentage.
Assuming river folds don't happen, you can try this comparison:
Saw Showdown and Won Hand
vs
Saw Showdown and NOT(Won Hand)
Now you can see what percentage you're winning at showdown. Do you feel like it's more common to lose with certain kinds of hands in this way? You could add a filter for a specific hand too and compare how things go with AK. If you do these as Hand reports you can see quickly whether the river is the deciding factor. You could even use our tag system with a little work to figure out the exact percentages -- add a tag to hands where you were ahead and lost on the river card (as it should be less than doing the other way around) and you can figure out with subtraction what percentage of total hands that is.