You have the innate ability to birth your babies. No question about it.
However, multiples sometimes can't get into the right position which can lead to complications during labor. If Baby A (the baby closest to your birth canal) is head down, you can certainly plan for a non-medicated birth. However, even with this plan and Baby A in the right position, you should consider having a catheter for an epidural inserted during labor.
You can birth your babies without medication, however with multiples, things can shift quickly and having the catheter already in place can provide assurance that you will not miss the birth of your babies. If Baby B or Baby A shifts and cannot get into position, it may be necessary to have an emergency cesarian birth. Having the catheter in place, so the epidural anesthesia can be administered quickly for the surgery, is important so you will not need to be sedated.
When talking to your doctor, discuss when a catheter should be put in and explain your wishes to not have the anesthesia administered unless you request it. The role of discomfort and pain during labor is actually quite important so choosing to just have the catheter without administering the medication is certainly an option. That way you can still have control over when you opt for pain intervention and have taken the proper precautions in case you need to shift your plans during labor.