Bot to load chunks and stop mobs from despawning when they go through nether portal.

I would like to see if anyone could make a plug-in that stops mobs from despawning when they go through a nether portal. I have a guardian farm but when the mobs go through the portal they despawn. A command like /player like in the carpet mod would be used to get a player to load the chunks and act as if it is an actual player who just went afl. Thanks for all of you effort that you might put in to this.