How to find dynamic port mappings when container has multiple ports exposed?

Rancher 1.x
1

I have a container with three local ports (2100, 2101 and 2102) that have different uses. When I configure Rancher to use dynamically assigned ports, how can I find which dynamic port is mapped to which local container port?

I can find in the API all dynamic ports for a container instance, but there is no way to link the port together… How do I find which port is linked to ie: 2100?

“ports”: [ 3 items
"2100/tcp",
“2101/tcp”,
“2102/tcp”
],

…

“publicEndpoints”: [ 3 items
{
“type”: “publicEndpoint”,
“hostId”: “1h2”,
“instanceId”: “1i7062”,
“ipAddress”: “172.16.1.241”,
“port”: 42416,
“serviceId”: “1s65”
},
{
“type”: “publicEndpoint”,
“hostId”: “1h2”,
“instanceId”: “1i7062”,
“ipAddress”: “172.16.1.241”,
“port”: 44404,
“serviceId”: “1s65”
},
{
“type”: “publicEndpoint”,
“hostId”: “1h2”,
“instanceId”: “1i7062”,
“ipAddress”: “172.16.1.241”,
“port”: 36566,
“serviceId”: “1s65”
}
],