Yes. With RSS.com you can have as many podcasts as you want under the same account. Keep in mind that to have multiple podcasts under the same account you must be on the Podcast Network plan.
Podcasters coming from the All in One Podcasting plan will be prompted to upgrade their plan the moment they add a second podcast. Likewise, podcasters on the free plan must sign up to the Podcast Network plan as well.
How to add an additional podcast
To add an additional podcast under your account, from an existing show, go to "New podcast" in your podcast switcher.
Once you've added an additional podcast, to switch and navigate between them, just toggle the podcast switcher and select the one you want.