"I don't want cows to be killed, I just want to eat beef."
"I want to eat beef." Is an expression of intention. It can arise without any reference to a cow.
"I don't want cows to be killed." Is an expression of intention. It can arise without any reference to eating.
Both these expressions can arise in close proximity to each other and when this happens some people will notice that there seems to be a conflict when considered together. My view is that intentions often conflict and this is a source of dukkha. Isn't conflict of intention one of the major causes of dukkha in the world?.....I want this, you want that.....
"I don't want the fetus to be killed, I just don't want to give birth to this baby."
"I don,t want to give birth to a baby." Is an expression of intention which might or might not be followed by an intention to have the fetus removed. If the intention to kill the fetus arises then that is an intention which is independent of not wanting to give birth since not wanting to give birth does not in itself mean that the fetus will be killed....could be that the decision is made to go ahead and have the baby even if it is not a perfect choice. Again, there seems to be a conflict and again it is by my view a source of dukkha..
My view is that both of these examples have two distinctly separate instances of two separate intentions arising and there is no reason that I can see to connect them logically in the fashion you describe. So I know that this is probably not addressing your question directly. If you can think of a situation where the two conflicting intentions are more closely coupled I'll give it some consideration.