Specify filename for midi output within lilypond file / Create multiple midi-blocks

[Hauke Rohmeyer]

Is there a way to specify the ouput filename for a midi file within a midi 
block?
I want to produce learning midis for a quartet from a single lilypond file
(I could write different files in which I include the music, but it takes a lot 
of time)
I found an answer to a similar question in the archives, which statet


"You can do everything in one run, but then you'll have file-1.midi, file-2.midi etc. I suggest you write a wrapper script to invoke lilypond 
and rename these appropriately. A better solution is scheduled for lily 2.9/3.0"

Is there a better solution?