84 suburban heater control valve?

[RNation]

Alright ready for my newest problem?...haha. My heater control valve leaks, and finding a replacement has proven to be difficult. All the units they sell at regular auto stores aren't the right ones. My sub has rear heat also so there's 2 heater cores. My heater control valve has 6 ports total (1 water feed, 2 feeds to the heater cores, 2 returns from the heater cores, and 1 return to the radiator) and the auto stores has 2 total. I saw one in a catolog that had 6 ports but I was told that it depends on the flow direction after the heats turned on as to whether it will work right or not.

So my question is, does anyone know if I can replace it with any 6 port control valve or where theres an aftermarket place with them available?