There is a tool available in the jrGroupToForum module - https://www.jamroom.net/the-jamroom-network/networkmarket/653/group-transfer-tools
- that will transfer Forum topics to Group Discussions so if that would work for you, take a look at that.
If you really need them to go to Blogs, a tool could be developed based on the the tools in this module. Unfortunately we have no immediate plans to do that unless it is sponsored by yourself. If you are interested in us doing that, let me know and I'll send you a quotation.
Paul Asher - JR Developer and System Import Specialist