Unfortunately, there isn't a way to merge the results between two studies. Even if all of the items appear the same, on the back end they are all assigned unique IDs that are used to store the participant information, so the two studies will look as different from each other as if they were completely unrelated.

As a possible alternative, the analysis spreadsheet generated in your Downloads tab is also unique to each study, so you could consider combining the data manually by making use of the downloadable spreadsheets.

Going forward, you may be interested to know that in a situation like this, you can collect data from the two different audiences in the same study and simply give each one a slightly modified URL that would assign each group a 'token' that would show in the Participants tab so you could select a subgroup for analysis. You can read about this here.