Complex sentence: In the kitchen, Sally and Jan talk about Sally's work, and, in Tamsin's bedroom, Graham and Si talk about Parsons, with Si revealing that Parsons was actually unpleasant to work for.
Split into simpler sentences: In the kitchen, Sally and Jan talk about Sally's work. In Tamsin's bedroom, Graham and Si talk about Parsons, with Si revealing that Parsons was actually unpleasant to work for.