In
portal/WEB-INF/conf/jcr/repository-configuration.xml,
you have to add parameter "analyzer" to each query-handler
config:
<query-handler class="org.exoplatform.services.jcr.impl.core.query.lucene.SearchIndex">
<properties>
...
<property name="analyzer" value="org.exoplatform.services.jcr.impl.core.MyAnalyzer"/>
...
</properties>
</query-handler>
When you start exo, your SearchIndex will start to index contents with the specified filters.