I need to add MX records to one domain which I have with name servers at ENOM with dns hosted serveric:

I am not able to add more than the @, * and only 1 mx record more.

I need to add three:

Example MX Level Mail Server
20 mx1.dnsmadeeasy.com
30 mx2.dnsmadeeasy.com
40 mx3.dnsmadeeasy.com

Does anybody know which can be the reason I am not able to do this simple task ?

Thank you