We know that the full wave function of spin particles have two parts. One is the spin part and another is the spatial part.
Let's assume I have given a wave function which is the spatial part:
$$\psi (r_1,r_2)= r_1^2+ r_2^2 - r_1 \cdot r_2 $$
The wave function is clearly symmetric.
Now let's assume I have two identical particles which have zero spins. If we want to write the full wave function, the spin part has to be symmetric, since we have zero spins particles.
How I can write the spin state of the zero spin particles which will be symmetric?