Good evening Corey and happy new year!
Yes, we can absolutely combine these accounts into one of the higher tiers.
This will probably make it much easier to manage for you.
As an FYI, when people want to upgrade their licenses, they get an automatic discount.
You can read more on that topic here.
Since you are in a very specific situation, the best solution would be to upgrade one of these licenses to the higher tier you are interested in.
Once that’s done, you will be able to assign you other sites to that newly upgraded license.
We would like to offer you a one-time discount (see the following private reply for more details) to make the transition smoother (considering the multiple renewal dates).
Hope that answers your question.
Let me know if there is anything else I can do for you ?
Best regards,
Geoff B.