If you put the comb with the queen cell, some comb with honey and enough bees in a two frame nuc or a "queen castle" or a "mating box" (depending on the bee supplier) or a standard box with a follower reducing it to two frames, you can let them mate the queen and care for her. What do you mean by "keep" them? Leave them in the cutout? One might be good insurance if you didn't see the queen.