How to match multiple series' in arithmetic operation?

I have two series:

  1. blah.*.foo
  2. blah.*.bar

* matches the same set of sources for both series. So, I would get a number of graph lines, one for each of those sources.

I would like to show the results of a computation, where for each source I have a calculation between these two series values, for each source. Something like this:

divideSeries(blah.*.foo, blah.*.bar).

My hope was that it would be recognized that all matching series should be divided and therefore a graph line should be produced for each source.

Sadly, that doesn’t work. I suppose it doesn’t realize that * in both series will result in the same set of values, and that it should create one division graph for each of the values.

Any idea how this could be accomplished?