Informix - get DB Server Name / Alias for connected Session

Question

I'm running an Informix Dynamic Server Version 11.50 on AIX with multiple DB Server Aliases listening on different tcp ports.

This is basically what I have in my sqlhosts file:

# dbservername     nettype    hostname         servicename        options
# DBSERVERNAME
infx_1             onsoctcp   host             port1
# DBSERVERALIASES
infx_2             onsoctcp   host             port2
infx_3             onsoctcp   host             port3

I want to log connections to the database, so I'm going to use the procedure below which I found here

This gets me most of the information I want, but it doesn't tell me whether the DB Server Name, or one of the DB Server Aliases was used when connecting.

Is there any way to get that so I can add it to the log?

CREATE PROCEDURE public.sysdbopen()

    -- Log session details on database connection
    -- Doug Lawry, Oninit Consulting, August 2020

    DEFINE session, process INTEGER;
    DEFINE dbname, client, program VARCHAR(255);

    -- Continue calling session after any error
    ON EXCEPTION
        RETURN;
    END EXCEPTION;

    -- Ignore high frequency or system users
    IF USER IN ('no_exceptions_for now') THEN
        RETURN;
    END IF

    LET session = DBINFO('sessionid');
    LET dbname = TRIM(DBINFO('dbname'));

    SELECT pid, TRIM(hostname), TRIM(feprogram)
    INTO process, client, program
    FROM sysmaster:informix.syssessions
    WHERE sid = session;

    SYSTEM
        'echo ' || '"' ||
        CURRENT :: DATETIME YEAR TO SECOND || '|' ||
        session || '|' ||
        dbname  || '|' ||
        USER    || '|' ||
        client  || '|' ||
        process || '|' ||
        program || '|"' ||
        ' >> $INFORMIXDIR/logs/connection.log';

END PROCEDURE;

I tried using DBSERVERNAME/SITENAME, but it always gives the DB Server Name, even if the connection was to one of the SB Server Aliases.