UI pushbutton toggles

In my lovelace UI - setup in yaml mode - I have an entity card with a two entities, a hot water switch and a countdown timer. I have set this up so that countdown timer is hidden by default. When hot water is switched ON the the hidden countdown timer is displayed and counts down from 1 hour , after which the hot water is automatically switched off by the countdown timer calling service.switch.turn_off.
What would be the best way of having additional toggle pushbuttons, one for 15mins, one for 30mins, one for 1 hour. When pressed a pushbutton toggles the two others to an OFF state. The active pushbutton determines how long the countdown timer should be, i.e. 15, 30 or 60 minutes.