A new adaptive rule for balancing the load on many parallel queues is designed. The queueing system can accommodate different types of customers where each type is persistent in joining a particular set of queues. The rule makes use of a set of bias levels to compare the queue lengths and makes use of the majority-vote rule for propagating the routing decisions to the different types of customers. Delay and blocking probability comparisons between this rule and three other adaptive load balancing rules, the JSQ (join-the-shortest-queue) rule, the GBQ (generalized biased queue) rule, and the MRT (minimum response time) rule, show that it is always superior under widely different conditions on a three-parallel-queue system.