Voices are normally channeled to front speakers. Surrounds are often “effects”. 

Can I changes this to remove the effects from the speakers and add the dialogue 

No, Sonos doesn’t include that as a feature. Surround speakers will always carry the information denoted as ‘effects’ by the content.

You could remove them as surrounds, the group the two rooms, but any TV content (the voices) would be delayed by at least 75 ms, which makes lipsync problematic, and for those who can hear both sets of speakers a bit annoyed.