I assume you mean on the hour and possibly half hour and quarter hour, not nonstop ringing for 3 hours straight. (8-11am)
I’m sorry you have anxiety and are in a hostel. Life must be tough at the moment.
I found the biggest help for me when distressed by something outside my control and I was spiralling, was to find a different way to experience it.
Reframing the bells as calling people to a place of sanctuary and safety might help. For centuries church bells have told people the time and called them to prayer and reflection. They are part of the fabric of our culture despite Christianity no longer being part of most people’s lives.
Whatever reason you are in a hostel, those bells are saying you’re safe from what you had to leave.
If you can find a way to think of them as a reassurance, you might find it better. After all, the times aren’t a surprise, so you know when they will chime.
Sorry if that sounds patronising, but it was a thing that really helped me a lot when I was in a bad state of mind.