Vr. fenestralis is one of the hardest plants to remove pups from. They sit very close to the mother plant with no rhizome whatsoever, so it is very delicate surgery, and yet you need a strong tool because of the size of the pups. I have never been able to do it without ruining the mother, but if it's bloomed-out maybe you don't care. At any rate, if they're still deep down within the leaves they're too small to come off yet. If it were me, I'd just let them go until the smallest one is at least half the size of the mother, and then dismantle the whole thing. It's kind of harsh, but unless someone has a better method that's the only way to avoid damaging the pups too much. There is very little margin for error on this plant. The only thing worse to divide is some of the Dyckias.

Ihave beensuccessful in separating pups without killing the mother. I remove the lower leaf sheaths around the pups, and gently move a pup away from the mother. If you do this carefully, you cansee the plane of separation. I use a diamond cut saw or weeding short saw to remove the pups. Becareful of the angle of the cut, staying parallel to the axis of the pup. I hve removed 8 pups in this manner. Good luck