I'm creating a word list that combines the most common 3000 Chinese characters into words, I can't seem to make it so the characters only appears once.

Column A: single character word list (一，我，你，们) etc.

column B: a dictionary that include 10000 words from the any characters (possibly even those not in the word list).

Column C: a word list that includes all possible combinations of characters from A that with column B（e.g. column A has 人， 民，理 and 物 but not 吾, so column C has 人民， 人物, 物理, but not 吾人).

I want to make it so column D has only on occurrence of a character from Column A. So 人民 appears but 人物 doesn't, while at the same 物理 appears. Any remaining characters can be left as single characters instead of words.

What do I do?