Not ideal, but you could adapt one of the build commands.
Adapt as in modify the compile or run command in /usr/share/geany/filetypes.*?
For now it'll probably only work if they match the 'standard' interpreter error/warning syntax.
I might be able to write a wrapper script to run the respective tool and reformat its output - however, I don't know what the "standard interpreter error/warning syntax" looks like... Also, If this is gonna be built into Geany soon, it's probably not worth the trouble!?