Codes generally do not allow for a macerating/pump toilet (like Saniflo) to be used under conditions where typical gravity toilets are possible. They are for basements, generally, or locations where the toilet is below the level of the sanitary sewer.

I think you might also have trouble getting approval for this from the condo board, even if it were allowed in your location (say in a single family residence). If they won't let you access a sewer line through a common wall, I doubt they will give the go ahead to a macerating toilet.

Is it the lack of a sewer line that is the correct size that is the problem? Because the drain in the kitchen connects to the sewer line, it's just smaller in diameter.

Thanks for the information. We were told that the kitchen drain will not connect to a sewer line...

Hooey. A drain always connects to a sewer line. It's a drain, and the waste water goes to the sewer. The issue is the size of the drain line, which won't support a toilet unless it's replaced back to the main drain. That requires demolition.