Connecting arduino to EV3 and Lidar sensor using I2C communication

Hi

I had a question concerning making communication between arduino (uno R3 or nano) and lego mindstorms EV3. For my project I use a lego mindstorms EV3 robot. My robot has to detect obstacles, which I' planning to do by using the Lidar lite v3 sensor. I was planning on connecting the Lidar lite sensor to the arduino for gathering distance measurements. My problem now is that the arduino has to communicate with the EV3. This can be done by using I2C, however I have already used the pins SCL and SDA for the communication between my arduino and Lidar sensor. Is there a way for me to use the arduino as a master to the Lidar sensor and as a slave to the EV3?

I have found that I could use the library: SoftI2CMaster for addressing multiple pins for I2C communication. If I use this library for making extra I2C pins (e.g pins A4 and A5), will these 2 pins work the same as if I would have used pins SCL and SDA?

Also they mention to use a pull-up resistor, why is that? I'm interesting in knowing why I would use a pull-up resistor here, whereas I would not have to use one when using the SCL and SDA pins. Is this because there is internally already a pull-up resistor in the arduino uno R3?

Or is there another, easier, way for me to use my arduino as master to the lidar sensor but as a slave to the EV3?

Thanking you in advanceā€¦