Here’s a helpful tip for what to do with unwelcome swarming bees. Backwards Beekeepers will rescue the hive and domesticate them, preserving the queens. From the website:
We’re a group of organic, treatment-free beekeepers in Los Angeles, with branches now forming in other cities. We’re “Backwards” because we rely on observation and natural practices to keep our bees thriving rather than pesticides, chemicals, or treatments of any kind.