Connecting a new I2C sensor to emonTH v2

Hi! My name’s Enrique.
I’m wondering if there is an easy way to connect a new I2C sensor to emonTH v2.
As far as I’m concerned, you can add multiple I2C sensors to the same Arduino pins bacause you can communicate with each one differently by using sensors adresses.
The problem is, I2C pins (PC4 and PC5) are directly connected to SI7021 temp. and hum. sensor and I can’t access them to add new devices, at least there’s no way that I can see.

Has someone found a solution to this?

Thank you so much.