This is still a challenge at the transcript level. In the Beta version, they are working with keeping the transcription by individual clips as well as a static transcript of a sequence.
If the sequences are the same timing, you can export the transcript from Sequence 1, and import it to Sequence 2. The transcript export you want is a .prtranscript, but it cannot be edited. In the Beta, they are also working on importing an edited transcript.