Co-chains are not yet available and full design is not yet available.
Note that to my knowledge channels on Hyperledger Fabric are not really private: orderers see everything. Orderers are the nodes that actually do the consensus. On Algorand, orderers would loosely match participation nodes. Algorand does not really have the notion of peers like Fabric has.
If privacy is needed against orderers in Fabric and against participation nodes in Algorand, I believe cryptography methods need to be used (such as encryption).