HDCD into Upsampling DAC?? Possible??

I own two CD players that I love dearly. My main unit is a Cambridge Audio Azur 740C; I think the best-sounding sub-$2000 player I've ever heard. Although I don't completely understand "upsampling", the 740C clearly brings out air and depth to all Redbook and most audiophile CDs. My second player is my faithful Arcam Alpha 8SE HDCD player. The Arcam is clearly inferior with most discs, but some of the better audiophile-grade HDCDs seem to have more "bloom" through the Arcam. As the 740C has digital inputs for use as a stand-alone DAC, would it make any sense to run the Arcam's digital out through the 740's upsampling DACs?? Would the Pacific Microsonics HDCD layer pass through and somehow enhance the already upsampled 24-bit 384khz output? Just a wild hair... Thanks.
You would not get the benefit of the HDCD encoding using the dac in the Cambridge.
I have a Cary 306/200 CD player/DAC that receives the HDCD into its digital inputs and outputs it that way, but I don't know think you would be getting the same thing by upsampling the redbook layer of an HDCD-encoded disk. I am quite certain that a DAC that does not have onboard HDCD decoding would be able to read that part of the disk. At least in my experience with the Benchmark DAC-1 that was true.