display multiple values from other worksheets

Hi,

I am trying to better manage some inventory and have created a workbook that has all my information. There are 4 sheets, each representing a location with identical rows and columns. What I am trying to do is create a totals worksheet in the same workbook that would display which of the locations an item is at. For example, if my widget is at location 1 and 3, the widget cell in my total sheet would display 1,3 or something similar. I tried using an if statement which can get the infomation from the other worksheets, but can not make it display multiple values if the statement is true on multiple worksheets. Is this possible to do?

I have included a sample workbook with my if statement included. Thank you for any help.