I am getting nearly weekly noise complaints from neighbors

So I own a 7-8 bedroom town house that is sandwiched between a hotel and a bunch of apartments and across the street from a hostel.

The problem: we get complaints about our guests noise. We let all guests know about this and to mind their noise at night but as it's a 7-8 bedroom, inevitably we get people making some noise. Even if they're not particularly loud, the fact that it's a big place means more people.

Anyway, the hotel next door blasted me a new one because a group of girls staying at ours decided to do some living room singalongs at 10:45 at night and needless to see, they're threatening to take this to the council and have been apparently collecting signatures for the nuisance.

The girls quieted instantly when I messaged but it's getting hairy.

I'm kinda of stuck as to what to do. We live in a relatively noisy neighborhood and all the houses are 150 year old Victorian houses all stuck together.

When anyone.complains about noise, we immediately inform the guest and usually it's fixed but then a new guest comes and the same problem persists. So... We seem like we're ignoring the neighbours.

At this point I'm tempted to throw in the towel and potentially sell.

The neighbour basically wants us to have someone on site all the time but it wouldn't be practical as it's advertised as a private home but we do have a property manager who lives 15 mins away.

Any advice would be appreciated.