wildcards in smtproutes file???

Hi friends,

I have a little problem routing mails. I need routing mail for many  
domains to an specific private ip address.

The problems:

- Is it posible set more than one route for a same domain and take in  
mind the secondaries, only if primary fails? If I only can set one  
route, if this mailhost fail, I can't delivery messages to this  
domain...

- I need routing mail to a few domains, wich have many subdomains:

1.xxx.com
2.xxx.com
{}
10.xxx.com
1.yyy.com
2.yyy.com
{}
7.yyy.com

(...)

Can I use wildcards for route all @*.xxx.com and @xxx.com to same ip?  
how should I do?

Thank you very much in advance,
Spamis