Update code in board

Hi,

I am currently doing a design with an FPGA to control a bus signal in
a control board industry. What the board can be updated easily by the
client and can be adapted to different teams. By this I mean that you
can turn on or off certain signals, as well as for other industrial
board, has a different processing of signals. I used the FPGA flash y
not ICSP.

What if someone can help me and explain how this could involve, for
example depending on which data you enter in a flash, the circuit
makes a different treatment of data bus. If such boards used for a
signal to some other individual, depending on industrial machinery.
Planned to implement some core microprocessor in the FPGA and the
flash is stored in the program for this microprocessor, but I find it
laborious and not know whether this task can be performed more easily.
¿Implementing a CPU as I have said?. ¿Structure of data in flash and
an interpreter in the FPGA? Any ideas?. Thank you.

Greetings
Antony