Hey there!
Sorry I was slow to pick this up again. I think the issue here is likely deeper than what you do with Schema. Schema, after all, simply exists to make NAP a bit clearer. I think the core question here is whether you are genuinely running two different businesses, in which case, you would have a unique legal business name, unique phone number and website for each. Google can generally handle two businesses occupying the same address. I don't recommend, at this point, creating a fictitious suite. Represent the business/es exactly as in the real world. Google has gotten better at not merging the listings of truly distinct companies occupying the same address provided all other signals besides the address are unique.
What Google would have a problem with would be a single company promoting itself as two companies. So, for the sake of example, let's say you are a landscaping materials company called Greenscape. You deliver compost, gravel, etc. You also do custom landscaping consultations. So, you've got two services (product delivery and consultation) operating out of your site at 123 Main Street. In this scenario, you are only entitled to 1 Google+ Local page. You aren't entitled to one for the delivery service and another for the consulting service. A business that decided to bend the guidelines on this would be in danger of punitive action on Google's part, which could hurt both listings they've created. I think the guidelines are very clear about this.
The only other proviso here is that merging is a possibility, even if it seems to be less of an issue now than formerly. So, there is a possibility that even if you are running two absolutely distinct businesses out of the same building, Google could mix them up, and the chance of that happening is likely greater if there is some unifying factor between the two businesses (two podiatrists, two auto service businesses, etc.). So, do be sure you're doing everything possible to keep two companies in this scenario distinct, including different legal business names, phone number, websites, citations and, of course, totally unique content.
Hope this helps!