Thanks for the responses. I did contact DVC and they told me that because there was already 4 people (2 adults, 2 children) on the reservation I could only add one more name, HOWEVER that person would also have to purchase the dining plan (I guess it is all or nothing?)
The rep suggested I call the resort directly but doubted that I could split the reservation. So I guess that leaves me with what you all have suggested. Either meeting up to pass the keys or leaving keys at front desk with name on them.
Is there a separate parking pass for the resort or do you just show key cards?
Just to prepare you, it's going to get *very* murky with Disney's My Disney Experience system in trying to "hand off" the reservation from one group to the other. It's not as simple as just handing over a set of key cards.
The system is designed so that everyone on a reservation exists in the MDE system as a profile. The hotel reservation, Magic Bands, Dining Plan, park tickets, etc are all linked to those profiles and talk to each other through the profiles. (For example when you scan a Band to enter the park, it uses it to look "you" up in the system to find your park ticket)
By default, everyone actually on the reservation will be issued MagicBands. People who don't want to wear the Bands can request a card at the front desk to take the place of the Band. But both the Band and the Card will point to the person who's actually listed on the reservation. There is no way to get them to point to anyone else.
You could *probably* get away with Group 2 using the Bands simply for room key access, but they'd have to keep their park tickets separate. If they wanted room charging privileges it'd get even more tricky.
If there's any way you can split up the reservation into two parts so that everyone in both groups can be listed on the reservation, that'll be the most seamless way of doing it.
-Rob