I was wondering if there is a limit to the number of HD streams that can be simultaneously utilized with DTV? I currently have two HD DVRs (family room and master bdrm) and two SD DVRS (children's rooms) and I am contemplating replacing the SD DVRs with HD DVRs. The two HD DVRs are already connected via Whole House DVR and I would probably do the same with the additional HD DVRS. My reasoning for not purchasing HD receivers instead of the HD DVRs is because of the potential scheduling conflicts when my children are connected to the whole house DVR system. Thank you.