Most blocks want to retain collective ownership of windows and the like because they can more easily control the design and look of the windows, and make sure they are doing their job in protecting common property.
You could possibly pass a by-law provided everyone agrees (four units of roughly equal unit entitlements effectively need unanimous agreement, since a vote of 25 per cent against would sink any by-law).
But why would the people with the widows that need replacing do so at their own expense when it could be shared?
On the other hand, if it makes the difference between getting it done or not …
Just make sure your by-law contains clauses ensuring that any changes to the look of the windows are agreed by a majority of owners and agreement that the lot owners will repair the windows at their own expense immediately after defects or maintenance issues become apparent.