Hiding Rows Based on Cell Content

In my File1.xls, I am using code I found that allows a user to double click in a cell to make a checkmark appear. (It is actually the letter "a" in marlett font.) For my application, the checkmarks can be added in column A, rows 1 through 25, of Sheet1 by double clicking. Therefore, based on user input, cells A1:A25 are either blank or contain the letter "a" if they are checked. Column B has text, Arial font, in each row. That works fine.

My goal is to link two Excel files. In my File2.xls, when it opens, I want its Sheet1, cells B1:B25, to show the text from cells B1:B25 in File1.xls, but only the rows where an "a" appears in Column A in File1.xls. The rows in Column A, File1.xls that are blank should be HIDDEN in Sheet1, File2.xls.

Ideally, I would also want Sheet2 in File1.xls,when clicked on, be the same as File2.xls, Sheet1.

I'm new to VBA and would appreciate your help. CJ