Do your best. Don't let guilt get you down. Plant natives on your rooftop and around your building. If you have the time see what native pollinators (if any) visit your rooftop and drop a little info sheet perhaps in your neighbours mail boxes to educate them a little about the plight of our local pollinators, to whom we owe our first attention. Most people want to do what's right but may not have the knowledge. Having honeybees on rooftops is a copy of what is done in the Northern Hemisphere but is not necessarily suitable or helpful here. If it is appropriate, you may be able to set up some native pollinator spaces and structures (which could be fun if you do it with others). There's plenty of info about if you're interested. Who knows, you could even attract the folks from Gardening Australia to help out and do a segment for their show. I am sure your situation is multiplied throughout our cities so it could be a win for many people and the little bugs.