It is late, and I am drinking, but I will try to frame this into a positive and possibly educational response.
Yes, one particular group runs the website in question, and to be frank, I don't know or care, who those particular individuals are.
It is not some nebulous over shadowing power group. Some of the girls and some of the locations work for them. Many other groups, and independents, do not, and they use it because it connects the provider with the customer. Think marketplace or craigslist. Don't throw the baby out with the bathwater.
The organized groups do have a basic working model. A shared location, several girls there, and they will have more girls than there are rooms that way when you walk in to see a particular lady you see some of the eye candy there and get all dumbed up and are thinking about seeing one of the other ones before you even interact with the one you are there to see.. It's an effective business model and it works.
The girls working there are not "owned" or slaves but rather independent contractors. They pay a fee for each session. Say a girl has a 200$/hr massage rate. The house may charge anywhere from 80-100$ per booked session. So while you think a 200$ hour long massage session makes that particular girl rich she's may be making only 100$ for the hour she spends with you.
Where these girls make a living is in the "upgrades". Anything beyond the basic service is theirs to keep.
You can have whatever current thought process you have that I am trying very hard not to disparage but if you continue with the attitude you espouse in your post you are cutting yourself off from many possibly wonderful and positive experiences.
Say I do meet with one who is part of these "oh so despicable" groups and she turns out to be amazing, and later on after learning how this lifestyle works, she decides to commit to this business and become independent and has a successful career that way, she likes me, and we've always had positive interactions, and now that she is doing this for herself, and remembers how I have always been a good client and a positive experience she "grandfathers" me in at her old rate.
You won't have that kind of good fortune with your current approach. I have several women with whom I have such a relationship with and some of these go back for many years.
Now as far as your comments about your "girls who use a phone number" comment there's a lot there that needs to be said. You enter that part of your comments as if this is some kind of magical elixir that makes things better and safer.
You are at risk whether it be communication via email or text. You get to decide your relative comfort vs safety level all by yourself.
I hide nothing from friends and family, I am not married, nor do I have kids. I am not the best source for someone who appears to be married to give you advice about how to "hide" what you are doing. Hopefully others can chime in on that.
Why would you ever use a texting app? That app is always on your phone. Email is safer if you don't load the email websites app onto your phone just and log into each time you use it. How many guys go down the suspicion road with their wives with something that starts as small as "Why does he have that app on his phone?"
It seems reckless to hobby using a shared phone plan but you seem to have grown beyond that and kudos to you by getting a burner phone.
Why would you keep something like that in your home? That's not potentially dangerous, your spouse would never go in the garage and find it wondering "Why is there an extra phone in our house?" Keep it in a locker at the gym, or at your desk at work.