Any way to have one Escalation Chain send emails to different people for different resources?

We do something similar, sending all alerts to Jira Service management where each customer has it 's own project.

What I did: at customer level defined a jira.project property which hold the project key. In the integration with Jira this property is used in the payload to address the correct project.

The payload then looks like this:

{
  "fields": {
     "summary": "##ALERTID## ##LEVEL## - ##HOST## ##DATASOURCE## ##DATAPOINT## ",
     "issuetype": {"id": "10285"},
     "project": {"key": "##jira.project##"},
     "customfield_10683": "##ALERTID##",		
     "priority":{"name" : "Mon-##LEVEL##"},
     "description": {
       "type": "doc",
       "version": 1,
       "content": [
         {
         "type": "paragraph",
         "content": [
           {
           "text": "##MESSAGE##   ##ALERTDETAILURL##",
           "type": "text"
           }
         ]
         }
       ]
     },
  }
}

Hope this helps :-)