You can have more than one AGENTRCV statements in the ESPPARM member. And you can have only one ZOSAGENT statements in the AGENTDEF member.
If you have multiple DE connections, you can define each one with its own COMMCHAN and EXTSCHED. Note: EXTSCHED is used to specify the mainframe user ID for security checking. It pairs with COMMCHAN statement.
One DE manager can define more than one ZOS agents.