InfoPath Dev

I have a form with two fields. The intent is that a user can paste data into textfield1, and textfield2 will rewrite and reformat it in such a way that it can be reused in another application. I've been able to successfully alter everything except when the data in textfield1 has linebreaks. I need:
string1
string2
string3
to be rewritten in textfield2 as "string1XXXstring2XXXstring3".

translate(textfield1,@crlf,"XXX") won't work since translate is one-to-one characters.
Any solutions are greatly appreciated, no code solutions even more so!

I found the answer in another post by user Qwerty.

Set the default value for textfield2 = textfield1 (this prevents the original data from being overwritten)

Then run the following rule on textfield2:
if textfield2 contacts @crlf
concat(substring-before(textfield2, @crlf), "XXXX", substring-after(textfield2, @crlf))

It continues to cycle through textfield2 until each linebreak is replaced.

Thanks Qwerty!!!!