After some checking, it looks like our servers won't allow customers to use multiple IP's for a single domain name. So, you'll probably have to continue to use ZoneEdit and DnsPark for that.
However, I'll add it to our features request list for you.
How to set your DNS entriesTo set up DNS for your domain, please follow the steps listed below:
1. Log into your Dynadot account. 2. Click on the "Domains" tab in the main menu. This takes you to the Manage Domain Names page. 3. Click on the link listed in the "Name Server" column. After the page loads, you should see your current name server choice close to the top of the page. 4. Scroll down to the "Advanced Dynadot DNS Services" section. 5. Enter in the IP Address of your web server in the first text box. If you have an Email Server or MX Record available for your domain email, enter in the hostname and the distance (otherwise known as priority) in the subsequent text boxes. You can also specify subdomain A records, CNAME records, and a TXT record. 6. Click the "Use Dynadot DNS" button to save your changes.