MX records for subdomain

I need to create MX records for a subdomain (So that I can use Mandrill service to parse incoming emails for my web app). However there is no such possibility in the current DNS interface. How can I get this done? Is there a workaround?

Many thanks in advance.

Regards.
Deepak Prabhakara.

add the subdomain under Domains>Manage Domains

then after the subdomain is added, click on Mail>Custom MX, find the subdomain in the list and click the edit button next to it.

Brilliant! Thanks!