Both cards share the same driver, so from DAW perspective both cards should be accessible.
But such a setup would have the disadvantage, that you have to work with two individual TM FX instances, where it is not possible to route inputs of one card to outputs of the other cards which is a limitation in terms of routing / the creation submixes with TM FX.
An alternative to this might be to use DAW mode and to route in the DAW. But then you do not have all the nice TM FX routing features anymore.
So to say, no matter how you set this up, you have limitations and you have to work in two separate TotalMix FX instances which needs more space on the screen.
Another thing is, that you need to clock sync both cards by using (sacrificing) one digital connection, ADAT or SPDIF to get the two cards clock synchronized. And you need to take care manually in the driver settings, that both cards use the same ASIO buffer size.
Definitively better would be to get a 802 or even better UFX II, then you have all in one package without any limitation.
BR Ramses - UFX III, 12Mic, XTC, ADI-2 Pro FS R BE, RayDAT, X10SRi-F, E5-1680v4, Win10Pro22H2, Cub14