Nowadays it is possible to send transmittal packages from the portal, either manually or thru script, or thru a workflow step.
The idea here is to have the possibility to initiate a review package from the power interface, so either in a workflow transaction or manually or thru script, you would select the leader and the optional/mandatory reviewers, the system would create the package, transfer the documents and send the notifications for the reviewers.
After finished the review, documents would optionally be transferred back to Meridian or stay in the portal for the next action as of nowadays.
That would bring some great possibilities of using the existent workflow engine of Power, like:
Scripting possibilities
defined workflow routes
integrations possibilities
with the great features of the review package in Portal, like
possibility to involve external and external users
real-time consolidation of comments
offline markup
leader reviewer consolidation