[Nauty] Searching for automorphisms of only one colour

[Christopher Jefferson]

Hi!

First of all, (as I'm sure Brendan reads this list), thanks for a very 
useful and speedy program! Its times like this that I am shocked at just 
how much computers can do (with the help of good programmers and good maths 
of course!)

My "problem" is that I have a coloured graph where the first "colour" 
represents variables and the other coloured nodes represent various 
relations. Stabilizing these other groups is quite easy, as the generators 
for them are separate, so I just cut them out of the answer. While this 
works quite well, I expect that if there as some way I could search for 
only the automorphisms of one colour, things would go even faster!

Is there a way to do this, or simple alteration I could make to nauty to do 
this?

Thanks in advance,

Chris