Based on the clue 'a group of 3 musically', what is the answer?

Based on the clue 'a group of 19th c authors is called the knickerboc...', what is the answer? Based on the clue 'a group of 2 ballplayers pitcher catcher is calle...', what is the answer? Based on the clue 'a group of 3 in power or a vehicle drawn by 3 hors...', what is the answer? Based on the clue 'a group of 3 men collectively responsible for the ...', what is the answer? Based on the clue 'a group of 3 under the zodiac sign of the lion', what is the answer? Based on the clue 'a group of 3 with or without a holy ghost', what is the answer? Based on the clue 'a group of 3rd graders got a bill passed to make t...', what is the answer? What is associated with: a group of about 155 rebels in texas confronted by mexican forces retreated into this strongho…