Multiple MX records pointing to multiple servers for a single domain
Solution 1:
Yes, you understand it correctly.
Sending E-Mail servers use MX records in order of preference defined within the MX records. The record with smallest precedence is used first, then the second smallest etc.
If two servers have equal precedence, the sending server picks a random server from the equal precedence server.
You can make forwarding accounts on server 1 that only forward all e-mails to server 2. This would effectively solve your problem.