Changing Data before it is used by PowerBI

I am using the Analytics connector for VSTS, and attempting to create a chart that shows me a trend by the first section of the area path.  Is there a way for me to mess with the data before it gets to the powerbi engine?  I want to convert strings like \something\a\b\c, and \something\w\x\y\z to simply \something, so I can group them all together. 

If I could get to a view I could do that, or if there was some level of mlddleware, on the powerbi side, perhaps I could do that.  But I certainly can't get to any vsts views and I don't know the powerbi side well yet.