Prevent an editor-assigned texture from loading into memory, load it on-demand later?

I've built a storybook-type app that moves between a number of fairly large textures (many of them 2k). I had originally programmed it so that anything far away from the current "page" is deactivated, and only activated once the user gets close to them. I had thought that this would keep the majority out of textures out of memory. Obviously, I was wrong--everything stays in memory from the time the app starts. This has turned out to be fine for any devices with > 512mb of RAM. Unfortunately, if I test on anything with 512mb or lower, it's an instant crash.

Everything was built in the editor--none of the textures are loaded programmatically (which would have made this a lot easier). Essentially, what I need to do is prevent every single GameObject from loading its texture when the game starts, and then tell each GameObject to load it's editor-assigned texture at a certain time. Is there a sensical way of doing this?