You can do this by adding another crypto map on your router. The crypto map name should be the same as the one existing in your configuration but you will need to change the number on that crypto map. This is because you can only apply one crypto map on your interface.
Your crypto map configuration should look like this:
crypto map MAP 10 ipsec-isakmp
set peer IP1, match, transform set, etc.
crypto map MAP 20 ipsec-isakmp
set peer IP2, match, transform set, etc.