Another question.. can someone please help me understand the difference between uploading docs through the GPTSimpleVectorIndex, vs. the ChatGPTRetrievalPluginIndex? It appears they all accomplish the same thing, which is answering questions based on the docs I provide?

Hi all - another question: I'm trying to "augment" the default chatgpt with some domain specific knowledge by providing them as documents and creating my own index. I tried GPTSimpleVectorIndex and ChatGPTRetrievalPluginIndex. I also played with different response types. It either answers questions strictly based on the information I provide, and anything beyond will get a response like "context has no information about ...". Or with the "generation" response type, it completely ignores the information I provide, and responds with a generic answer.. Is there a way to have it do both, i.e. the "augmenting" behavior? Much appreciated!