Renamed items won't stack when thrown on the ground (may cause lag)

Short Summary

I was building a redstone mechanism using a tutorial from the Youtuber "Sethbling" called "Smart Item Payment Machine in Minecraft" for my adventure map. I wanted to create a system, where I toss in a renamed item into a hole, where the items stack so they don't move along and activate a signal to prevent a a door to open for example.

So items that are renamed won't stack on the ground, making it possible for griefers to lag a server by spamming the items on the ground. It also won't let my system work, because i only want specific, renamed items to work with the machine.

Steps to Reproduce:
1. Rename any item at an anvil (it has to be a stack of 64 at once!)
2. Throw them on a ground
3. They don't stack like normal items do to prevent lag and item spam on multiplayer servers.