According to page 12 of the IC-765 instruction manual, connectors are provided for breaking the receive connection between the antenna tuner and the receiver circuit--you could put a protection circuit and an receive antenna switch between those connectors. You want to look at section 4-7http://www.aytechnologies.com/TechData/RIP-1.pdf
Here is a commercial protection circuit you can buy. A receive antenna can actually pick up a watt or more of signal from a nearby transmitting antenna--more than enough to burn out an unprotected receiver.
Zack Lau W1VT