Make a new font.
Go to Element/Font info
Choose Lookups/GPOS
and Add Lookup

Choose Pair position (kerning)

In window Kerning format choose Use a matrix of kerning classes

In fields First character I put D and O, and in Second character C G O Q. FontForge set the kerning to -110, I changed it to 10.

In Kerning Metrics window I wrote OQ

You can change the kern value moving the green line between chosen letters

In window Kerning by classes you can see the result

In window Font information/Lookups/GPOS you can right-click the lookup and choose Save Feature File (or only choosen lookup)

Saved

The important part of this file looks like this:

lookup kernHorizontalKerninginLatinloo {
  lookupflag 0;
    @kc0_first_1 = [\D \O ];
    @kc0_second_1 = [\C \G \O \Q ];
    pos @kc0_first_1 @kc0_second_1 22;
} kernHorizontalKerninginLatinloo;

feature kern {

  script DFLT;
     language dflt ;
      lookup kernHorizontalKerninginLatinloo;

  script latn;
     language dflt ;
      lookup kernHorizontalKerninginLatinloo;
} kern;

As you can see there is one class -left=first- with /D/O and one class -right=second- with /C/G/O/Q and the kern value between them is set to 22.

It is :) Most powerful tho little buggy
don't know how it looks under mac, here for win: http://typophile.com/node/84219

thank you thank you thank you thank you!

One lookup for all classes you want to kern. You can create the second lookup for Greek script and the third for Cyryllic script. See Brill font by John Hudson as the recent and elaborated example.