match, concatenate based on filename

[Matt]

Hi All, 

I am trying to concatenate several hundred files based on their filename..  Filenames are like this:

Q1.HOMOblast.fasta  
Q1.mus.blast.fasta  
Q1.query.fasta  
Q2.HOMOblast.fasta  
Q2.mus.blast.fasta  
Q2.query.fasta
...
Q1223.HOMOblast.fasta  
Q1223.mus.blast.fasta  
Q1223.query.fasta

All the Q1's should be concatenated together in a single file = Q1.concat.fasta.. Q2's go together, Q3's and so on...

I envision something like

for file in os.listdir("/home/matthew/Desktop/pero.ngs/fasta/final/"):
	if file.startswith("Q%i"):
           concatenate...

But I can't figure out how to iterate this process over Q-numbers 1-1223

Any help appreciate.