Can I use multiple SMTPs?

[Penicillin]

Hello
I have two SMTPs servers, the first is unlimited but bad, the second is limited (300 emails/day), very good and fast.
I want to use the good one for verification and passwords emails and bad one for other things like posts notifications, contact us, ...
Can I edit register.php to do that? how?

Thanks

[Dismounted]

I don't believe this can be done without a fair bit of modification.

[Penicillin]

I don't believe this can be done without a fair bit of modification.
Can I delete (vbmail) in register.php and replace it with my SMTP code?

[Dismounted]

You could try, I have not done it before.

[Penicillin]

It worked perfectly.
Thanks for your replies.