Mutual exclusion is a pretty common term for this concept.

There are no doubt more elegant ways to solve (or optimize) it, but this is a fairly straightforward solution that prevents the master and slave from having simultaneous control.

^{simulate this circuit – Schematic created using CircuitLab}

Mutual exclusion is a pretty common term for this concept. IBM has a patent on a more complex concept related to the use of mutually exclusive redundancy in a plural "voting" context for error detection. This concept also frequently finds use in the context of functional safety standards, such as IEC 61508 or ISO 26262.

There are no doubt more elegant ways to solve (or optimize) it, but this is a fairly straightforward solution that prevents the master and slave from having simultaneous control.

^{simulate this circuit – Schematic created using CircuitLab}