I do consider myself to be pretty tough cookie. I have very high doubts that only 1 tickler can come even close to breaking me. After all, sometimes when my gf is tickling me, she tells me to lay still, put hands above head and don't I dare to lower my arms to protect myself. Or to move my feet. Unless I'm unaware about some secret tickling technique I have never experienced, I will have doubts that only 1 tickler can come even close to breaking me. First few minutes are most intense, but once my skin gets used, it is game over for tickler and his hopes of breaking me. Sensations on which I can't get used to have too low intensity when done by only 1 tickler.
For more ticklers I can't really say, but I assume they could do it, especially if my gf tells them how to get me. She does think she could make me even pee myself if she could lay her hands on some bondage table and have several sadistic dommes at her disposal. One can only dream 😀