Is there is a way to upload my own panoramic images of our hours/building using Google Street View API, then use Google Street View Engine to navigate through them?
Officially you have to create tiles for your Panoramic image to become streetview controlled:
Providing Custom StreetView Panoramas
Setting up a set of custom panorama imagery involves the following steps:
Create a base panoramic image for each custom panorama. This base image should be at the highest resolution image with which you wish to serve zoomed in imagery. (Optional, but recommended) Create a set of panoramic tiles at different zoom levels from the basic image. Create links between your custom panoramas. (Optional) Designate "entry" panoramas within Google's existing Street View imagery and customize links to/from the custom set to the standard set. Define metadata for each panorama image within a StreetViewPanoramaData object. Implement a method which determines the custom panorama data and images and designate that method as your custom handler within the StreetViewPanorama object.