Binding Multiple Keys to one command (alt+left)

[Faranox]

Is there a way to bind multiple keys, not like a = c, b = c, but a + b = c.
Alternatively is there a way to bind the back and forwards keys (not arrows, but function keys that are mapped to back and forwards) to things ingame. Those keys input alt+left for backwards and alt+right for forwards.

[danijelbogosavljevic]

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[Mahasamatman]

I'd say that ANTIFA and BLM are alt-left