Proper way to format a letter with multiple addresses?

Type the first name/address 5 vertical spaces below the date. Leave one blank space, then begin the second name/address. Leave one blank space before the subject line or the salutation.

If you have more than three names, line up one column of names/addresses at the left margin (in the same way a name/address would normally be lined up), and put a second column of names/addresses to the right of those. The horizontal left margin for the second column should allow for about 1" of white space between the longest line of text in the first column and the left margin of the second column. If address content will not allow the columns to end on the same line, the content with the longest content should always be the left column.