Using VHD disk as a centralized backup device?

i have 2 physical servers (3rd will come later) and 2 hyper-vs on 1st one. I would use Windows Server Backup utility for backup all systems. Was thinking about to buy NAS, so i bought it, Synology 12bay system, but it comes with SMB2 only, so 2012R2 doesnt support backing up to SMB2 (smb3 is expected). So i think to create one VHD disk on first mashine and backup all into that VHD. What do you think, is it ok? Or no-no?

Thanks