HOA fees used for some homeowners

I live in an association that has no common area. There are homes that back up to a main street and next to that street is an easement with a sidewalk. In the last HOA meeting it was definitively stated by the city that the easement area was not a common area and that the lawn and sidewalk maintenance was the responsibility of the homeowners who have property adjacent to the easement (much like that in front of peoples houses). For the past two years the HOA has been using the HOA funds to mow and clear snow from the sidewalk and easement area for these homeowners while the people who do not have properties on this easement just pay for it without any benefit. Since it has been established by the city that these easements are the responsibility of the homeowners, is it legal for the association to use funds to maintain these easements?

This is one single street with 24 homes in a huge subdivision that has no other HOA's in it. The sidewalk on the other side of the street is maintained by individual home owners as per city rules. Declarations contain no wording on easements because the city governs easement rules (no trees or fences with 30ft of street, etc...) By city law you have to clear snow within 24 hours after the snow end.