Control more than 3 relays?

[turbogrill]

Hi,

What is the best approach of controlling more than 3 relays from RCP?

So far my options are:

1. Use the 4 analog/PWM output and a relay board such as, https://www.amazon.com/JBtek-Channel-Mo ... 00KTEN3TM/
It's a waste to use those outputs for driving relays...

2. Get a Arduino and a CAN shield
Send CAN messages to a Arduino that drives a relay board.
Very flexible and can add plenty of relays but a little more complicate.

Is there any other easier way? I know there are I2C/SPI boards, can RCP speak SPI/I2C easy?