|if all the files are in same directory and you want to search all text files then multiple ways.|
1) Just modify your command a little bit ...
type *.txt | find "Rule Title" >> newfile1.txt
2)Use for loop for all the files in that folder..
for /f %a in ('dir /b *.txt') do type "%a" | find "Rule Title" >> newfile2.txt
3) Use for loop for a list of files, suppose list.txt contain the list of files you wanna search, it could be the file name or full path including quotes.
for /f %a in (list.txt) do type "%a" | find "Rule Title" >> newfile2.txt
* If you use above commands in batch file then use %% instead of single %.