Nested fuzzy inference systems

New user here. I am interested in nesting Fuzzy inference systems or
use the output of one FIS as the input for the next FIS using Fuzzy
Logic Toolkit and Matlab.

Ex rule
1. if inputA=m and inputB=n then outputA=x
2. if outputA=x and inputC=y then outputB=z

I can create the FIS to produce outputA but how can I get this value
into the next FIS. I am eventually going to have many inputs and it
becomes hard to follow the logic if I try to have multiple inputs in
one FIS and only one output.

William Kinney
.