Backward pass for this setting

I have 2 models m1 and m2 and 2 losses l1 and l2
I want to train both models jointly.
m1 needs to be updated using (l1 + l2) and m2 only by l2.
To achieve this, I have 2 optimizers o1 (for m1's parameters) and o2 (for m2's parameters)
Is the following approach correct for achieving what I want?

y1 = m1(x1)
y2 = m2(x2)
loss1 = l1(y1, y) # y is ground truth
loss2 = l2(y1, y2) # l2 works on the outputs for m1 and m2
loss = loss1 + loss2 

Here, I make the assumption that d loss / d m2 will be same as d loss2 / d m2

This seems to be correct.