Dell c6220 minimum nodes

Hi,

I have a c6220 with 2 x 2u nodes. It has expanded backplane, NOT direct. Each node currently has 12 drives. Is it possible to have a single 2U node to see all 24 drives ?

Basically it is cheaper to have a c6220 rather than r720xd. So looking to switch over to r720xd once they becomes available from my reseller. In meantime, I like to set it up as if they were a single server with 24 drives. Is that possible with c6220?

Thanks