How to merge 2 columns into 1 but not really (split one into 2)

OK odd title, I know but not sure how else to put it.
I have many columns ranging at about 40-50 rows but I have one column at about 3X that, 150 rows. This means when I head to that one I have to scroll down and down. So what I would like is for that column to be split into 2. Still under the same column title, and when I do a 'sort alphabetically' they will all go into their place without spoiling anything.
Thanks

There is nothing private about the workbook. Normally such a thing is not done on Excel but on some database program since there are no formulas or even numbers.
You wrote, "Include a BEFORE sheet and an AFTER sheet " well I can't show the after sheet since this would suggest I know how to do it. Take a look at column ''T" I would like to have 2 columns "T"--If possible actually named "T" and "T" but I think this is not possible or maybe named "T1" and "T2". But hopefully it gives you an idea of what I mean.
Since I can't do a "After" sheet what I have done for to help is I created 2 worksheets. The 1st is how mine is now. On the 2nd I created a new row So now, on this 2nd one, all that was under "T" is now split into 2 some under "T" and some under "U" but they should be all "T" (Of course in this 2nd file all U's are under V now, and all V's are under W etc. etc. which is not what I want.

popipipo like may people in Holland, your English is great.
If I may ask, What is the purpose of having it all in 1 column (and why did you leave rows, 3,4,5, empty)?
This is my database of films I have seen in the last few years (with many missing). Since i am terrible at remembering many titles, especially non-English ones I have it so I don't buy/download/watch films already seen.
So when I am not sure of a title I go to it. If it starts with the letter 'D' I go straight to the letter D. Usually I could see it right away so I don't need to do a search for it (Except for the letter 'T'). That is the sole purpose of this spreadsheet (which should be a database but my knowledge of that is even worse and my trial with it was not successful)