I am designing a control circuit for a [Sabertooth 2x60 motor controller](https://www.dimensionengineering.com/products/sabertooth2x60). When this controller is in analog mode, it runs in full reverse (0v control signal) until my software starts and applies 2.5v to the signal pin. I have currently integrated a [voltage divider](https://learn.sparkfun.com/tutorials/voltage-dividers/all) and a [relay](http://www.circuitbasics.com/wp-content/uploads/2015/11/SRD-05VDC-SL-C-Datasheet.pdf) circuit to apply 2.5v from a source independent of the computer (5v vin divided by two 47kOhm resistors) which works but I am hoping to get rid of the mechanical component (relay) if possible. 

It has been a long time since I have worked with transistors and mosfets and was hoping if someone could assist me in the design and if there is an IC I can use? To recap requirements; Apply 2.5v from a voltage divider circuit until the software applies a 5v signal (Digital I/O) to the relay which then switches vout to use the analog output of my control software instead? There will be two analog inputs to my control circuit, one 2.5v from the voltage divider and one 0-5v from my software. Using a Hi/Lo pin, I want to select which input the circuit should output.

Thanks in advance for any assistance you can provide me :)