Merging multiple UV'd objects while keeping the UV channels separate

Okay, I know I worded that weirdly, but I can’t think of any other way to say it.

I’ve got 2 models all UV’d and textured and I’m ready to export them to Team Fortress 2. I want them to be 1 model, but they need their own UV channels so I can use 2 texture maps on it at once. When I merge the models their UV space gets combined into 1 channel rather than separate uv channels.

Does anyone know how to do this? I’d really rather not have to re uv one of my models.