TWI Slave To Master Dynamically

Hi, I'm working with the nRF52840-DK and need to be able to receive (slave) and generate (master) data on the same I2C lines. I'm aware this target doesn't support multi-master mode.

Independently, implementing the master or slave modes is relatively simple following the examples but I was wondering if it is possible to switch between instances dynamically? Or is there any other way to achieve this?