How to set boundary condition which includes two PINN outputs

[anyay]

Thanks for the excellent library!
As shown in the title, here are the boundary conditions used in my study:

In the first boundary condition, cij and cij+1 are outputs, z is one of the inputs, and tS is the time consumed by one period.
I don't know how to set this boundary condition. Could you give me some suggestions? Thank you!