Shoutbox

A batch file mainly automates file handling and stuff. It isn't suited for file contents manipulation. Making a batch file for this is possible, but it would require a very dodgy and way too complicated routine to pull it off.

If you want to do this with something similar like batch files, use/make a VBS script instead.

Note: Any automatic tool which does this either needs to be XML aware (and check for the order of those time/date tags)... or you can make it very straitforward and crude but then you should be very carefully in what files you merge and which not with this tool(/script).