Filter of xml in input

[Stompero]

Hi, I'm new in Splunk and I'm looking for some help for the following use case:
at Splunk indexes all new files in a folder, each file represents an event, but the files that arrive are many.

  I would like to index only the files that contain a data value to a tag (eg " Error </ MessageType>" I would like to index only the xml files that contain this string). I can do this? how can I solve this problem?

[sbrant_splunk]

You may want to consider a scripted input to apply some additional logic to the collection.

http://docs.splunk.com/Documentation/Splunk/latest/admin/Inputsconf