Originally Posted by McKBrew
At the SAME pressure- If you plan on blasting it with 30 PSI to force carb, the Y will feed 30 PSI into the other, which I don't think you want to be serving on. If you have a Y with on/off valves, you could close off the one being served, open the one you want to force carb and blast- switch the carb valve off change pressure back and open to serve.
A secondary regulator could be added with a short pipe. I haven't priced out which would be cheaper- second regulator and fitting, or but a new regulator and sell the other.