Hi,
Thank you very much for your response.

ChaincodeA only makes use of GetState calls, so I'm not modified the ledger.
I can't install chaincodeA in channel-2, I need to keep it isolated in another channel (channel-1).

I'm getting this warning when I call chaincodeB from channel-2 (logs from Org3Peer):

2021-06-28 08:52:56.258 UTC [policies] SignatureSetToValidIdentities -> WARN 0d7 invalid identity: certificate subject=CN=Admin@...,OU=admin,L=New York,ST=New York,C=US serialnumber=249376481855686298878436353699729151421 error="MSP Org4MSP is not defined on channel"

And the policy error:

 Failed to handle INVOKE_CHAINCODE. error: failed evaluating policy on signed data during check policy [/Channel/Application/Readers]: [implicit policy evaluation failed - 0 sub-policies were satisfied, but this policy requires 1 of the 'Readers' sub-policies to be satisfied]

And the Application policy:

Application: &ApplicationDefaults

    ACLs: &ACLsDefault

    ...

    # ACL policy for chaincode to chaincode invocation

    peer/ChaincodeToChaincode: /Channel/Application/Readers

    ...   

Policies:       
    Readers:           
        Type: ImplicitMeta          
        Rule: "ANY Readers"