Constructing BGP Peer Group Templates

Following example shows how to use BGP peer group templates to reduce configuration commands and apply configurations as a bulk to a group of neighbors. But the neighbors within a group must be in one autonomous system. You cannot group members from different autonomous systems.
You can apply specific policies per member if you want too.

BGP builds one set of UPDATE messages for a peer group, applying routing policies for the entire group, rather than one router at a time, thereby reducing some BGP processing and memory overhead.

Starting from BGP AS config command;
R1(config)#router bgp 65000

Creating peer group and assigning AS for the group;
R1(config-router)#neighbor MY-GROUP peer-group
R1(config-router)#neighbor MY-GROUP remote-as 65000

Defining the members of the group;
R1(config-router)#neighbor 2.2.2.2 peer-group MY-GROUP
R1(config-router)#neighbor 3.3.3.3 peer-group MY-GROUP
R1(config-router)#neighbor 4.4.4.4 peer-group MY-GROUP

Applying group wise polices;
R1(config-router)#neighbor MY-GROUP update-source Loopback0

Applying neighbor specific polices;
R1(config-router)#neighbor 2.2.2.2 password cisco123

Note that for different address families, you need to configure the peer groups separately within those address families..