How to define a condition for a covergroup (using iff)?

[RahulPatel]

In reply to darp4u:

cp1 : coverpoint type_a iff(type_a == XYZ){
                       bins out_bound[] = {[10:18],[37:45]};
                       }
cp2 : coverpoint type_a iff(type_a == PQR){
                       bins ou_bound[] = {5,[10:18],25,[37:45]};     
                       }