Ok, I understand. You create a lot of instances and they are automatically named as "FBI_0, FBI_1" etc., but you want to call them, for example, ENGINE_0, ENGINE_1 etc.
I recommend you to create all instances, then export project to a XEF file. XEF is a XML-file with UTF-8 encoding. Than you can open it with any text editor and replace "FBI_" to anything you like (for example, to ENGINE_). Good luck!