I have been at a birth where cord clamping was delayed for around 1 minute, and then cord blood was taken for treatment (of another sibling) so to do both is possible. However if you want to do delayed cord clamping all you have to do is insist on it. Have it in your birth plan and, if possible, have midwifery care rather than obstetric care as midwives are usually very used to delayed cord clamping. If you have obstetric care you will still have a midwife so ensure that they are aware of your wishes but it is so commonplace nowadays to delay cord clamping that I doubt it will be an issue for you.