Nest speakers can't stream music at home when I'm streaming on my phone

I have my Google Home speakers setup with my own and my girlfriend's Google accounts. I've added various music streaming services to them, but I primarily use YouTube Music for myself. When I'm at work listening to music on my phone (YouTube Music) and my girlfriend is at home trying to listen to music through the Nest speakers on Spotify, it causes my music to stop playing. Is there a way around this that does not require paying more money for a family subscription? I know that if I were to leave Google Home, I would be able to listen to music uninterrupted and so would she. Is there some setting I'm missing? I was thinking to just setup the Amazon Echo I have in a drawer somewhere, but that's a lame solution. We have 2 Nest speakers and one of the displays as well, and they all become basically crippled.