You can't. The only reason it does random on stages like Shadow Moses Island, Smashville, Mushroomy Kingdom, and Spear Pillar is because they have multiple stages within them, chosen randomly (Smashville is time-based though).
Jungle Japes is a single stage, so only the one you choose over it will appear. You must use it over a multi-stage.
If you want to use Spear Pillar, you'll have to use them over Spear Pillar or .rel them over Smashville stages, Mushroomy Kingdom, etc.
Doing that is tricky, and I believe each stage must be used along with the .rel or it can cause freezing. (For example, only .rel for 3 stages when Smashville has about 5)
If you have no idea what I just said, then just use it over the stages it initially came with.