lookup GSUB5f1 {
    ignore sub three four;
    ignore sub four five;
} GSUB5f1;

lookup GSUB5f2 {
    ignore sub [a - z] [A - H] [I - Z];
    ignore sub [a - z] [A - H] [I - Z];
    ignore sub [a - z] [I - Z] [A - H];
} GSUB5f2;

lookup GSUB5f3 {
    ignore sub e;
} GSUB5f3;

feature test {
    lookup GSUB5f1;
    lookup GSUB5f2;
    lookup GSUB5f3;
} test;