If the models are separate from each other, for instance, not sharing components, you can just simply store them in a regular python dictionary rather than in a nn.Module class.
If you need them to be submodule of a nn.Module containing class and want to store them in ways other than direct attributes (e.g. a dictionary attribute), remember to use this method to bind them to the container: http://pytorch.org/docs/master/nn.html#torch.nn.Module.add_module 64