Hi Shawn,
Do a "sh ver" and under licensed features, you will find out how many "IKE peers" you can have.
Remember that when adding crypto maps, you can have only 1 per interface. You need to keep the crypto map name the same as the one already applied. You can change the priority / sequence number of the crypto map to something else.
Look at the hub PIX configuration in this example to get a better understanding of the process in this configuration example.
http://www.cisco.com/en/US/products/hw/vpndevc/ps2030/products_configuration_example09186a0080093bd3.shtml
Paras