Construct a musical piece by amalgamating the designated alphabetical representation and the supplied musical theme.
X:1
L:1/4
M:2/2
K:Gmin
['G A', 'G A']  
X:1
L:1/4
M:2/2
K:Gmin
|:"^A""_NB1" G A | B G B c | d2 d c/B/ | A B c d | B G G A | B G B c | d2 d c/B/ | A G A ^F | G2 :: 
"^B" d e | f e f g | f2 f e/d/ | c d e d | d2 d/c/d/e/ | d2 c2 | B2 G A | B G B c | d2 d c | 
 A B c d | B G G A | B G B c | d2 d c/B/ | A G A ^F | G2 :|  