Zimo and Digitrax are the only 2 DCC systems that I know of that support what you want to do.
With the digitrax, you'd need to use their transponding features. You set up your BLD168s like normal for block detection, then add RX4's for transponding.
I'm not familiar with how you'd do it with ZIMO, but I'm pretty sure its possible. They tried to get it approved by the NMRA, but issues with the implimentation kept it from being approved as an NMRA standard.