Stale topic for existing producer

[Casey Daniell <ca...@hotmail.com>]

BackgroundWe have a few consumer that *used* to consume a particular topic.  This topic still exist and the consumers still exist, however, these consumer no longer subscribe to the topic. When we check the offset for the Consumer Group, kafka.tools.ConsumerOffsetChecker,  ZK believes this tier is falling behind even though it's no longer attempting to consume this topic. 
Kafka StackKafka 0.8.1 with Zookeeper 3.3.4; Simple Consumer
Question We keep track of the lag using the  kafka.tools.ConsumerOffsetChecker to ensure we don't have a systematic issue we need to investigate. Is there any way to expire  stale, or no longer consumed, topics per consumer group?
Casey