Just go to Lowes or Home Depot and get a three outlet industrial plug. Single to triple. Below are some examples.
http://www.lowes.com/LowesProductComparisionCmd?catalogId=10051&langId=-1&storeId=10151&...
There are also single to triple with a short cable. Again industrial style. I have two in black. They work VERY well. And I a few of the above style version. Also work Very well.
But that is just my opinion and experience.