I am in the same boat with two loan origination systems. For the 2017 data, I was able to get a test pipe eliminated text LAR from both and copy/paste them into one text file. It went through the CFPB beta 2017 portal fine. Just remember not to copy/paste the first line of the 2nd LAR.

Since the portal with the 2018 portal won't be out until next summer, we are also planning to sign up with Questsoft to run the 2018 edit checks early in the year.