Must I pay for my neighbours’ balcony maintenance?

Hello all, first time user and have checked the threads to see if this has been covered.

In a block of 15, ten water side units have balconies (added 4 years ago, a separate long story that included the building being vacated for 2 months), 5 do not (the street side).

Maintenance is required on the water side balconies (rust, lighting etc) and it is to come 100% from strata. In effect, the entire building is paying for their upkeep. Is this correct?    Should the owners on that side establish a separate sinking fund for balcony works?

The building is in the Nth Sydney council area, NSW.  Many thanks for any advice.