Create A Batch File That Runs 3 Other Batch Files

I am trying to create a batch file that runs 3 other batch files. Right now, it works fine using the call command on each other batch file. However, these other batch files take awhile to run. and so the entire process takes a very long time, since each "sub" batch file is run only after the previous one is finished.I was wondering if there is a command or way to start a batch file fro the top-level batch file, then go on and start the next batch file before the previous one is finished. In other words, I want the sub batch files to run in parallel in the background. (similar to the '&' in Unix).