Is it possible (with a mod, I suspect) to link two input devices to one source, so that either of them can activate it?

For example, as it stands with vanilla portal 2, if I were to throw down some stairs and attach two buttons to it, BOTH buttons would need to be pressed in order for the stairs to activate. I would like a system where EITHER button could be pressed to activate them, not both.

Essentially what I want is OR gates, not AND gates.