Conversion to multiple formats

Long time lurker, first time poster.

I tried searching for a way to convert a file format to multiple other ones in one go, but I have been unable to do so.

I read almost everything on a kindle, but I heavily use text to speech and have had issues with it not working properly on both kindle devices and kindle apps, so I started converting my azw/mobi files to epub and running them through Marvin or MoonReader when needed but I like saving both the mobi and the epub.

I've been converting them individually, but I was wondering if there's a way to setup the process to do both automagically.

Thanks!