Its quite simple. You just have to edit your local configuration file app/etc/local.xml too look like this:

<config>
     <global>
         <cache>
             <prefix>apc</prefix> 
             <!-- this prefix should be unique for each Magento  using this server -->
             <backend>apc</backend>
         </cache>
         <!-- ... another content of your local.xml -->
     </global>
 </config>