Simple or multiple sensors for transport Integration?

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I’m currently working on a custom component to get the next bus at the nearby station.
I’m using template-entity-row to display the first and the second bus.

Capture d’écran 2020-05-01 à 12.55.08

What is the best approach to display the second bus : A second sensor or an attribute in the first sensor ?

If I’m using a second sensor I will have this :

 secondary: 'Next tram {{ states("sensor.tram_to_la_poya_next") }}'

And if I’m just using an attribute of the main sensor I will have this :

secondary: 'Next tram {{ state_attr("sensor.tram_to_la_poya", "next") }}'

Thanks !