From my understanding, a player becomes eligible for the veterans list if they have given 10 years of service to their club and they turn 30 in the relevant playing season. Clubs may list as many veterans as they like, however the amount not included under the salary cap will be reduced on a sliding scale dependant on how many veterans they have. If you have 2 veterans, 50% of their salary will not fall under the salary cap, if there's 3 players it's 33%, 4 players 25% and so on.
Shaun McManus was born on 9 February 1976, making him eligible to be listed on the veterans list along with Shane Parker.
It's unlikely that Bell will ever be listed under this unless he plays on for another 5 years, which is doubtful.