How to create expression with Geneva datasource?

I am working on the latest version of Grafana in Windows to create an expression with a datasouce of Geneva. I want to calculate a division between two queries and want to use something like $A{dimension1=xxx} / $B{dimension1=xxx}, but it returns a 500 error. Any hints on how to choose a specific dimension in the expression which uses Geneva as datasource? Thanks!

That usually means the plugin does not allow that feature.

Can you try the binary transformation feature or do that math within Geneva itself?