Setting and Accessing a Global Variable

I am using the webMethods developer version 4.6 on a Windows machine. I would like to set a variable (preferably a string variable) in one flow service then access the contents of that same variable from another flow service. Therefore, the variable would be global to that package or folder.

I thought that a Record Reference would do the trick but it looks like that data structure does not persist the data from one flow service to the next.

Thanks for your help.