Redirect SMTP server traffic based on mail domain in telnet commands

We maintain 2 companies SMTP relay infrastructures through the same LTMs. Up until now we've instructed our administrators to point multifunction printers at the DNS record that mapped to appropriate company located in that building. Now these companies are sharing an office space so we're wondering if we can point all MFP devices at a single VIP and use iRules to look at the mail domains continued in the telnet commands (MAIL FROM:mailbox@companyA.com or RCPT TO:recpient@companyA.com) to select the appropriate nodes or pools that contain respective SMTP servers?

Unfortunately we cannot do this level of filtering at the SMTP servers level. If we have to tell the companies to maintain separate MFP devices we will, just hoping to avoid the extra cost if our LTMs can solve this with filtering.