aggregating data for features using UCSC Table Browser

[M.N.]

Does anyone have a good way to aggregate features from table browser, I feel like their is an easier way than scripting it based on raw data from the FTP? Can this be done via the web-browser?

Basically just need to get the average phastCons for a (long) list of features in a bed. The subtrack merge seems like it should but it doesn't.

Much appreciated.