fonttools/Tests/feaLib/data/PairPosSubtable.fea

languagesystem DFLT dflt;
languagesystem latn dflt;

@group1 = [b o];
@group2 = [c d];
@group3 = [v w];

lookup kernlookup {
    pos A V -34;
    subtable;
    pos @group1 @group2 -12;
    subtable;
    pos @group1 @group3 -10;
    pos @group3 @group2 -20;
} kernlookup;

feature kern {
 script DFLT;
 language dflt;
 lookup kernlookup;

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