my @matches = $string =~
    /
     ^                          # beginning of line
     (\d{1,5})                  # 1-5 digit number
     \s+                        # gap
     (?:                        # group
        ([A-Z0-9()-]{7})        # 7-char thing
         \s+                    # gap
        ([A-Z0-9()-]{7})        # another 7-char thing
     ){1,45} # 7-char thing     # up to 45 groups
     $                          # end of line
    /gx;