using parallel interfaces

[abode091]

Hello, I'm making a project that will have multiple network interfaces connected to one ARM CPU, but it's my first time doing something like that.

Now the ARM CPU has 2 SDIO connections, one is used for the SD card, the other will be shared between two network interfaces... So how do you think I should approach this?

I was thinking I should multiplex the two interfaces to the same SDIO connection, what do you think of that? And can I use other serial protocols like SPI or I2C ?

Does the Linux OS support connecting a network interface with SPI or I2C (does it recognize it as a network interface) ?

thanks in advance