Not sure this is going to yeild the result you're hoping for....you already have the two assemblies [commonly refered to as "sub-assemblies"]....and assuming they're different.
The actual assembly file doesn't take up much space on a PC, as the component [par, psm] files themselves are where the physical size is carried.....assembly is just a "configuration" [a viewport, if you will] of those files.
Design Manager Streetscape Ltd
Solid Edge ST10 [MP7] Classic [x2 seats]
Windows 10 - Quadro P2000
Greg, I would work on simplifying or remodeling the geometry/elements you have if you're having RAM issues even with the very high end BOXX setup you're working with. From what I've seen, your models have a lot of splinter elements and unnecessary geometry that is repeated dozens to hundreds of times and really bogs down the software.