I'm not sure if this is very good or not. The chorus started out as a song about Shirinai Heinrich, and the way her children wanted to become pilots so they could fly to the heavens and see her again. Somewhere along the line however, it turned into a love duet... so I sincerely doubt it would be between the twins.
At any rate, thanks for reading this ^^-Kelly

"Beyond"
Possible Opening/Ending for 
Ai no Kachi
--------------------

My life for that moment,
Of your heart beating with mine,
A memory to hold with you,
The very cease of time.

Waiting, hidden in the crowd, 
Watching, the grin you believe is so sly,
Hoping tomorrow will be our time,
Fantasy of us, existing only in my heart.

But, beyond tomorrow, before my past
Hiding tears, beneath these silken smiles,
Beyond the chains of yesterday's hurt,
These wings I have, will bring me to you

Holding on to dreams of you,
Long after I awake,
And sigh into my pillow, 
Like I begin each new day

Remembered silent looks,
Touching hands by mistake in line,
The scent of your hair as you walk by
Fantasy of us, existing only in my mind.

But, beyond the stars, beyond my fears,
Beyond my dreams of you, beyond this life,
Beyond the pain, beyond the past,
These borrowed wings will take me to heaven for you
     
Beyond the lies, beyond the tears,
Beyond the fantasy and into the blue sky,
Beyond the lone heart, two beating as one,
These borrowed wings will fly me to heaven with you