postfix mynetworks

[msf004]

I was reading the article about Zimbra MTA MyNetworks here: ZimbraMtaMyNetworks - ZimbraWiki

and the mynetworks setting article led me to the article about Subnet Notations here: Subnetwork - Wikipedia, the free encyclopedia

My questions is:

I have a remote machine for which I would like to relay messages through my Zimbra Server. The remote macine has two block of IP addresses:

1.2.3.35
1.2.3.36
1.2.3.37
1.2.3.38
1.2.3.39

on subnet 255.255.255.248

...and...

5.6.7.130
5.6.7.131
5.6.7.132
5.6.7.133
5.6.7.134
5.6.7.135
5.6.7.136
5.6.7.137

on subnet 255.255.255.0

I am not a subnetwork-IP-address-notation-expert, so do I need to worry about understanding how to add my addresses to the mynetworks using the:

1.2.3.{blah}/{more blah}

...and...

5.6.7.{blah}/{more blah}

methods, or is it good enough to simply add each IP address individually?

Thanks,
-Marc