You can use the Mule file transport with inbound and outbound endpoints to move files, and either set a dynamic path attribute for the outbound, or use choice routing based on the original filename. You will have the original file name available as #[message.inboundProperties.originalFilename].
UPDATE (example flow):
<file:connector name="File"/>
<flow name="exampleFlow">
<file:inbound-endpoint connector-ref="File" path="/tmp/1" responseTimeout="10000" />
<set-variable variableName="myPath" value="#[message.inboundProperties['originalFilename'].substring(message.inboundProperties['originalFilename'].indexOf('_')+1)]" />
<file:outbound-endpoint path="/tmp/#[flowVars['myPath']]" responseTimeout="10000" connector-ref="File" outputPattern="error#[message.inboundProperties['originalFilename']]"/>
</flow>
UPDATE 2:
to use choice routing replace the above file-outbound with something like this:
<choice>
<when expression="#[flowVars['myPath'] == '1']">
<file:outbound-endpoint path="/tmp/1" responseTimeout="10000" connector-ref="File" outputPattern="error#[message.inboundProperties['originalFilename']]"/>
</when>
<when expression="#[flowVars['myPath'] == '2']">
<file:outbound-endpoint path="/tmp/2" responseTimeout="10000" connector-ref="File" outputPattern="error#[message.inboundProperties['originalFilename']]"/>
</when>
</choice>