Looking for research for separating conversational audio files
The task of separating a conversation with multiple speakers taking turns is called Speaker Diarization. This is different from Speech Separation, which is a special case of Source Separation, refers to separating out multiple overlapping/concurrent sources from an audio stream.
Some free datasets include

ICSI Meeting Corpus
AMI Meeting Corpus
VoxConverse

More can be found in the Github project wq2012/awesome-diarization.