how to use multiple update process chain?

[derrick cui]

Hi, 
I need to do three tasks.1. add-unkown-fields-to-the-schema2. create composite 
key3. remove duplicate for specified field
I defined update.chain as below, but only the first one works, the others don't 
work. please help. thanks
<requestHandler name="/update" class="solr.UpdateRequestHandler" >
  <lst name="defaults">
    <str name="update.chain">add-unknown-fields-to-the-schema</str>
    <str name="update.chain">composite-id</str>
    <str name="update.chain">deduplicateTaxonomy</str>
  </lst>
</requestHandler>
<updateRequestProcessorChain name="add-unknown-fields-to-the-schema" 
default="${update.autoCreateFields:true}"
         
processor="uuid,remove-blank,field-name-mutating,parse-boolean,parse-long,parse-double,parse-date,add-schema-fields">
   <processor class="solr.LogUpdateProcessorFactory"/>
  <processor class="solr.DistributedUpdateProcessorFactory"/>
  <processor class="solr.RunUpdateProcessorFactory"/>
</updateRequestProcessorChain>
<updateRequestProcessorChain name="composite-id">
  <processor class="solr.CloneFieldUpdateProcessorFactory">
    <str name="source">_gl_collection</str>
    <str name="dest">_gl_id</str>
  </processor>
  <processor class="solr.CloneFieldUpdateProcessorFactory">
    <str name="source">id</str>
    <str name="dest">_gl_id</str>
  </processor>
  <processor class="solr.ConcatFieldUpdateProcessorFactory">
    <str name="fieldName">_gl_id</str>
    <str name="delimiter">-</str>
  </processor>
  <processor class="solr.LogUpdateProcessorFactory" />
  <processor class="solr.RunUpdateProcessorFactory" />
</updateRequestProcessorChain>
<updateRequestProcessorChain name="deduplicateTaxonomy" default="true">
  <processor class="solr.UniqFieldsUpdateProcessorFactory">
    <str name="fieldRegex">_gl_dp_.*</str>
    <str name="fieldRegex">_gl_ss_score_.*</str>
  </processor>
  <processor class="solr.LogUpdateProcessorFactory" />
  <processor class="solr.RunUpdateProcessorFactory" />
</updateRequestProcessorChain>
thanks