[yt-users] Can I specify the particle type when loading data?

Hi yt users, I'm working with a particle dataset and I'm wondering if it is possible to only load a certain type of particle fields from the snapshot as my dataset? For example, there might be 'PartType0' and 'PartType1' in the snapshot, but I only want to load 'PartType0'. The reason I want to do this is that, to my understanding, the octree of the particle dataset is constructed adaptively according to the number of particles, including all types of particles in the dataset. But I want the octree constructed only according to the type of particles I'm interested in. Is it possible? Thanks, Bili