Hartmut, what you have posted above appears to be circular. The Review Upload view is set to display the peerReviewGroup field, which in turn is set to display the Review Upload view and so on. If that's the case it is incorrect.
So suppose you have a view for students to upload a review and you want to display in this view a peer submission. You need a view "Peer Submission" to display the peer submission for the reviewer, and a dataformview field peerSubmission for embedding the "Peer Submission" view in the "Review Upload" view. The "Review Upload" view should contain the pattern [[peerSubmission] ] which would display the "Peer Submission" view. This is required because the entry in the "Review Upload" view and the entry in the "Peer Submission" view are from different groups, and if the activity is separate groups entries from different groups cannot be displayed together without the bypass provided by the dataformview field.
In addition, if the peer submission is from another group, you can't filter by group in the dataformview field, because that will return only entries from same group of the reviewer. The filter condition should be something like
AND EGR name = [[reviewee] ]
where reviewee holdes the reviewee group name in the Review entry which the "Review Upload" view opens for editing.
The workaround is to add to the views you want to display via the dataformview field something like:
<div class="hide">[[EGR:name] ]</div>
So this should be added in the "Peer Submission" view.
Hope this makes sense.