Installing shut-off valve in main line

I live in a condo that is plumbed with PVC and has a shut-off valve in line with the main pvc pipe coming into my unit. This valve is leaking like all the others in this building and when shut off, will leak into the system building up pressure and presenting a hazard for flooding. We shut them off when leaving for the end of season.
My question is possibly stupid, but I wonder if there is a kit available to install a valve into a line that is pressurized without shutting off the main valve to the building. This would be into the 1 in. poly line below the current valve. I have looked on line at various valve suppliers but can't find anything like this.
I can visualize a possible solution similar to a saddle valve concept but have never seen one or found any as above on the web. Thanks a lot and let me know when you stop laughing. Jim

The thing I'd do is deal with the condo association to replace the valve with one that works properly. There is no excuse to have valves that do not shut off completely. The only right way to fix this is to change the valve with a good one. I'm not sure I follow exactly what you have in mind, but it would be a bandaid repair at best. This is not a rocket science job, and INMHO, the association should fix it, if not you could easily do it.

Thanks Gary. Will try this. Jim B