How to distinguish different identical sensors in a CAN bus network?
The CAN protocol doesn't carry any information in a frame other than the address of the unit sending the message. However, it provides up to 8 bytes of user defined message area. So if you wish to unambiguously transmit a temperature reading you should do so in the data message area and append that reading with source information.

CAN is a peer-to-peer protocol and doesn't necessarily carry anything outside the message area that can be relied upon for recognition of any party on the bus.