Linking to column in another Excel file + removing empty cells

Hi all,
I need your help in excel linking:
Let's say I have 2 files: Source file and working file. In source file there are some text names in a column that are updated once in a while.
1. I need to create a column in "working file" such that is taking values from column in "source file" even when "source file" is closed.
2. It should take only non empty values, because I need to create a cell with validation list that consists of text names from the column.

Solving attempt:
By searching some solutions in forum I found that the first part I can do in the following way: copy column from "source file", select in "working file" a "paste special" option and choose "paste link". It works, but the problem is that it imports all the column: if in "source file" the column consists of words "a" (cell A1), "b" (cell A2) and all other cells in A column are empty - in "working file", after linking, it appears as "a" (cell A1), "b" (cell A2) and all other cells in A column are "0" (zeros) till cell A65536. And I need that in "working file" column after linking will appear as "a" (cell A1), "b" (cell A2) and all other cells will be empty, so by setting one of cells in B column to be a list (by "Data" - "Data validation" - "List" ) - it will consist only from "a" and "b", and not from "a", "b", "0", "0", "0", .... (65534 zeros).

Any help is appreciated. Thanks!