OpenBGPD how to announce prefixes to only one peer?

[John E.P. Hynes]

Hi Misc,

I'm setting up peering with one of our ISPs that splits "local" routes 
and the full routing table up into two peering sessions.

If I announce my network with "network 1.2.3/24" in the global section 
of bgpd.conf, it announces to, predictably, both peers.  I am only 
supposed to announce my networks to *one* of these, and not the other.  
It isn't clear to me from the manual how to do this.

What am I missing?

Thanks,

-John