You have several options.
You could use the Radial Catapult:
https://www.radialeng.com/product/catapult
or you could use some form of AOIP like Dante but you will need to then get the audio out of the Dante network, converter it to analogue and patch it into the analogue 888's or C24. That isn't as simple as sending audio from the director to a Dante receiver.
Receivers only listen, they don't route.
You will need some way to send the Dante signal from the receiver back to a transmitter.
Any Dante audio interface will do that, you might be able to use Dante VIA or Dante Sound Card in some combination of hardware.
I use Focusrite AM2's for headphone sense but if you want bidirectional communication then something like the Focusrite X2P would work, but it isn't cheap.
My whole studio is Dante'd up so it is a simple process but if this is the first time you are going to be using AOIP then the former option of Radial Catapults is probably cheaper and easier.
If you don't *really* care about SN (ie just for foldback and talkback) then you can use a pair of 4 channel Catapults as a stereo send and return by using XLR gender changers on one pair of IO. It will be noisier but probably not a massive issue in this instance.