Georges...
No matter what you do in such a situation you WILL get complaints due to the nature of intelligible /coherent sound vs diffuse/broadband sound such as white noise. Pulsing, rhythmic sound such as music will be perceived as "loud" simply because the nature of the rhythm attracts the ear, EVEN AT AN AVERAGE SPL MUCH LESS THAN WHITE NOISE.
The only real recourse after you have done your best to tame your levels as much as possible is to work with the neighbors in good faith and within any existing statutes governing sound levels and times of operations.
In the end, such issues fall on subjective perceptions rather than objective, measurable criteria. It's more diplomacy than anything else.
See if you can give the hotel guests passes/discounts/coupons so the hotel can become an ally rather than an adversary.