Combining two entities?

I have two LightwaveRF wall switches (called, eg, Door A & Door B) that control the same central light - and this produces two Entities.

If I tap on the Door A or Door B entity within Lovelace, or turn on one of the wall switches the light turns on and the relevant icon changes colour BUT the other entity does not change.

Whilst I understand why this might be so, I would like to create a third entity that combines the two - so that whichever physical switch is turned on, the third icon changes colour to reflect the change in state. I would also like this third icon to turn the light on & off.

How might I best achieve this? Do I need to use a Lighting Group, or perhaps a Helper?

TIA

If they are switches you will have to use “Switch as X” to convert your switches to lights before creating a light group.