The Tigase server can, not only, accept connections from external components, it can also open connections to external components.
To make the Tigase connect to external component you have to change 'listen' parameter to 'connect' and of course you have to tell where to connect - the address of the external component:
--comp-name-1 = ext --comp-class-1 = tigase.server.ext.ComponentProtocol --external = devel.tigase.org:muc-secret:connect:5270:muc.devel.tigase.org
Assuming the MUC component listens on the port '5270' at the DNS address: 'muc.devel.tigase.org' the Tigase will connect to the component.
You can of course set as many as you need external components to which you want the Tigase to connect to:
--comp-name-1 = ext --comp-class-1 = tigase.server.ext.ComponentProtocol --external = devel.tigase.org:mucsecret:connect:5270:muc.devel.tigase.org, \ devel.tigase.org:pubsub_pass:connect:5271:pubsub.devel.tigase.org, \ devel.tigase.org:msn_pass:connect:5272:msn.devel.tigase.org
If external components run on a separate machines you can of course us the same port number for each of them.