Hi reclaimit,
Thanks for contributing to our forum. While we have not developed any special functionality geared toward allowing multiple users to use one Auctiva account simultaneously, I don't see any reason why you could not have a couple coworkers or employees create listings through your account at the same time.
As long as you do not have multiple people working on the same saved listings at the same time, I do no anticipate you will encounter any problems when having multiple people create listings through your Auctiva account.
I hope this helps. If you need any further assistance with your account, please feel free to contact our customer support team by mousing over the "Help" tab within your account and selecting the "File Support Case" option.
-Mike