Setting up ITS connection to one SAP system with multiple clients

Hello,

We use one system, in which every customer has its own client. I am not much experienced with ITS

i am trying to understand how is the ITS configured to connect to different clients in one SAP system

In IIS i have the following entry WGATE_DEV_XXX,

for this entry in the ITSRegistry.xml i have different URLs of type

c100.DEV.mydomain.com

<value name="Port" type="text">80</value>

<value name="ScriptPath" type="text">/ebp/scripts/wgate</value>

<value name="InstanceName" type="text">DEV_XXX</value>

c101.DEV.mydomain.com

<value name="Port" type="text">80</value>

<value name="ScriptPath" type="text">/ebp/scripts/wgate</value>

<value name="InstanceName" type="text">DEV_XXX</value>

and so on, where c100 stands for client 100 in DEV system

Apparantly these URLs are for same system, but different clients. Can you help me understand how the ITS knows that if i click the url beginning with c100 it has to log me to client 100? i have been unable to find this in any config file.