The answers to the clues below will have something in common.

1. Great, Wailing, or Berlin
2. Pearly, Golden, or Straight
3. They can be raised, lowered, or passed
4. Hog, fund, or row
5. Unhappy at the top of your voice
6. Australian tourist magnet
7. Good ones make good neighbors, according to Robert Frost

Answers:

1. Walls
2. Gates
3. Bars
4. Hedges
5. Railing
6. Great Barrier Reef
7. Fences 

Credit: LA Times Crossword
Sylvia Bursztyn and Barry Tunick
KEEP OUT  (adapted)