Add a second y-scale unit to Graphite graphs?

Hi there,

I am playing around with graphite templates and I wanted to improve the provided standards.
E.g. I don’t like to have to many multiple graphs just for icmp / ping / hostalive. So I tried to build a combined one with rta and pl in one graph.
Generally it worked out, but I couldn’t find anything in graphite to have a second y-scale unit line?
So on the left Y-axis having e.g. the units for the rta and on a right Y-axis having the % for pl?

Did anybody made something like this?