Ambisonic - is it possible to multiply a custom first order SH?

So if I understand correctly, ambisonics on the Quest are encoded as first order SH and then converted to binaural audio at runtime. What I wonder is whether somehow a multiplicative first order SH can be set to alter the binaural rendering at runtime (for example to simulate acoustic occlusion or draw the user's attention in a particular direction)?

If so, how?