Yes you can run multiple chains on one peer, all you need is to produce a configuration for each one of them and make your peer to join it. Just follow the following steps:
You need to provide chain configuration within [ configtx.yaml ]
Use [ configtxgen ] to produce create channel transaction and updates for anchor peers
configtxgen -profile PeerChannelProfile -channelID YourNewChannel -outputcreateChannelTx=newchannel.tx
where PeerChannelProfile is the configuration profile you have defined in configtx.yaml file.
Now an update is needed for anchor peers per organisations depending on he number of organisations as following:
configtxgen -profile PeerChannelProfile -channelID YourNewChannel -outputAchorPeersUpdate=Org1MSPAnchor.tx -asOrg=Org1MSP
The above steps need to be repeated for each organisation.
3. Now when you have create channel transaction you can actually make your peer to join the network by:
peer channel create -o orderer:7050 -c YourNewChannel -f newchannel.tx
This will produce the genesis block for your channel
4. Make the peer join it:
peer channel join -o orderer:7050 -c --blockpath YourNewChannel.block