of course it does not belong to gambling board, people thought its a gambling post simply because op mention lottery, perhaps it doesn't have anything related to gambling. the op would have just make the post without involving lottery because this is just a contribution that involve coin flip to know who to take first.
It is not really lottery though because lottery does not give you a guarantee that you will win but this system seems like you know you will be given a chance to get all the money, you are just not sure when. It is a gamble in a sense that we are talking about work salaries because what happens if there is an emergency but it is not your turn yet?
that's why it is not advisable to participate in such contribution using all your salary. Most guys will offer all their monthly salary to the next person hoping to get all back during their turn, but of course that is not good because if emergency comes and there is no fund, it will definitely going to affect such person. So The best way to do such contribution is to divide your salary by 3 use 1 part for such contribution and use 2 part for yourself sothat when there is an emergency the person will not be looking for where to get fund to bail himself out but he will use some percentage out of the 2 he has to sort himself out.