Remember that online the linking reservation thing doesn't always work and it still wants you to pay for CRT and the dinner shows even if you have a dining plan. Make sure you check before you accept the reservation online that you are not paying in full for it. If the website still wants you to pay in full, you will have to call.
If you're booking for persons in two rooms, book one restaurant reservation for the entire party. You do not have to link to two room reservations. If the linked room reservation has dining plan added, it should not charge you for anything, but you would need to leave a credit card number to hold the reservation. If the linked room reservation does not have dining plan added it will charge you for the whole party. No way around that except booking two separate reservations at the restaurant and if you do that there is no guarantee your group will be placed near each other, although you can ask.