Using Hyperpixel with additional i2c devices


I have been playing with i2c devices connected to a Pi3b+ along with the Hyperpixel 4 touch display. The mapping of i2c-3 to i2c-1 using the command provided on the learning page works fine for me

sudo ln -s /dev/i2c-3 /dev/i2c-1

except that this link is removed on rebooting the Pi. I am using Raspbian Stretch (updated in the last week). How can I get this link to persist over reboot/shutdown-restart cycles please?