How to design a safe RF switch using latching relays?
simulate this circuit &ndash; Schematic created using CircuitLab

Figure 1. Switching logic.

I have no idea how you would use relays in an antenna circuit but the logic you require is shown in Figure 1. It uses only two changeover relays - one single-pole and one two-pole.


  How to design a safe RF switch using latching relays?


You don't explain why you need them to latch.


  I was thinking of doing something like this and applying AND or NAND to the control circuit based on the state of the relay's contacts.


If the electronics fails then your circuit fails in an unsafe manner.