Mapping multiple pins to a single function

[Inguld]

I'm designing a PCB with 3 sockets into which daughter-boards will be inserted. Each daughter board has several pins which could be simple logic inputs or could be UART or SPI pins.

I'd like the ESP32 to be configured in software to interact with these pins as appropriate.

My idea is to connect all the pins (15 in total) to the ESP32 and then use the internal GPIO matrix to set up the correct mapping.

Since SPI allows multiple slave devices, I'd like to map several pins to one SPI. Speed isn't a huge concern for me so I'm fine with the tradeoffs of using the GPIO matrix.

Looking through the technical reference manual and the forums (found this thread), it seems that mapping multiple functions to a single pin is supported (in the case of inputs) but I can't find any information about many pins for a single function.

Is this possible?

[ESP_Sprite]

For outputs, you can map multiple pins to one function. For inputs obviously you can't.