I asked this question
You answered “Therefore we do say shehechiyanu on a peach, and most other fruits because of this reason.” I’m asking a different question, which requires some study to answer. If we already said a Shehechianu on a peach, can we say another one on a nectarine? M’stama not?
You didn’t write the fact that you already said shehechiyanu on the first type.
In any case the answer to your question regarding the peach and nectarine are called different type of fruits, therefore they get a separate shehechiyanu, (although it is controversial, the minhag however is to make a shechiyanu on both. However on different types of apples don’t unless they taste very different than each other, such as one is sour and the other sweet.
See Sharei Habracha 20-13,14. R’ Y. Cahen shlit”a