Running on different port with ASMTP

I beleive I can get Exim to run on both port 25 and 2500 with this setting.

daemon_smtp_ports = 25 : 2500
acl_smtp_rcpt = check_recipient
acl_smtp_data = check_message

Now my other question is can I enable ASMTP on port 2500 but not support it 
on port 25?  When a user connects to port 25 and tries AUTH I want to refuse 
it.  When they connect on port 2500 I want to allow it.

Any easy way to do that?

THanks.

Matthew