This is how you can only leave one instance of a repetition open for translation. The rest will be locked and you will then pre-translate this content once the translations are completed.
The workaround should be following:
1. Open the jobs in Memsource Editor or Web Editor
2. In the Filter, set Sort by Most Repetitions
3. With your mouse, select all the repetitions (repetitions are marked with two blue arrows) – click on the number of the first segment and scroll down to the last repetition, press SHIFT and click on the number of the last repeated segment.
4. Press CTRL+L to lock all repeated segments
5. Filter for Segment Status → 1st Repetition
6. Select all (CTRL+SHIFT+A)
7. Unlock these (CTRL+L)