Nimble Different compiler backend for different files

[xyz32]

Is there a way to have different nim files compiled with different backend, 
inside a nimble project?

I know that if I have a test.nim file and a test.nim.cfg. I can add `cc = gcc` 
to the cfg file to chenge the c compiler.

Is there a way to have the file compiled with a different backend?

ex:
    
    
    nimble build
    a.nim -> c backend
    b.nim -> js backend
    c.nim -> c backend
    ...
    

Thanks.