elasticsearch 部分密钥弹性搜索Kafka连接接收路由

我正在编写一个简单的卡夫卡连接器，源作为卡夫卡主题，目标作为弹性搜索

卡夫卡主题

   Name: my_kafka_topic
   Key as String :  A-1234, A-2221, B-3333, B-4444, C-1222, etc.
   Value  as Json : { "key1": "value1", "key2":"value2"}

我想根据键的部分值将事件从我的输入卡夫卡主题路由到多个弹性搜索索引，即

A-1234 event should be send to my_es_index_A
A-2221 event should be send to my_es_index_A
B-3333 event should be send to my_es_index_B
B-4444 event should be send to my_es_index_B
C-1222 event should be send to my_es_index_C

我无法通过任何转换实现这一点