You have to bring out each segment as a cluster group and make it optional.
Each segment is self contained.

"company" \s* : \s* 
( \d+ )                       # (1), Company req'd
(?:
   .*? 
   "address1" \s* : \s* "
   ( .*? )                       # (2), Addr optional
   "
)?
(?:
   .*? 
   "country" \s* : \s* "
   ( .*? )                       # (3), country optional
   "
)?
(?:
   .*? 
   "Name" \s* : \s* "
   ( .*? )                       # (4), Name optional
   "
)?