There are only two HGVC properties in SE (Atlantic Coast), Florida...
1 -- Plantation Beach Club at Indian River Plantation (Guide, p.72) is an affiliate. Its not online, so you have to call to inquire. Availability is described as "limited, meaning some owners there are not HGVC members.
B -- HGVC at South Beach (Guide, p.70) is two side-by-side art-deco era hotels on Ocean Drive, across from the beach. IIRC, you can generally find space, provided you book early enuff.
I've also seen Open Season there for both (thru the "classic" reservation system), but more so for South Beach than PBC-Indian River.
You may want to use a SW Florida affiliate at Marco or Sanibel/Capitiva Islands as an alternative.
The Guide:
http://multimedia.hiltongrandvacations.com/mg/Book_Reader.cfm?BookId=3