How to emulate a switch on power line
If you can use low-side switching, you can use an N-channel MOSFET in this configuration:







simulate this circuit &ndash; Schematic created using CircuitLab

R1 is added as a pull-down to ensure LOAD2 gets turned off when the switch is open. If LOAD1 has a low enough impedance to ground when off, you can omit R1.

If you must have high-side switches, the simplest configuration I can think of right now requires 2 P-channel MOSFETs:







simulate this circuit

If V1/V2 exceed the gate/source breakdown voltage, you can add another resistor R2 to form a divider with R1, or do something fancier like using a zener diode if V1/V2 can have different voltages. This doesn't appear to be the case for you so I've left them off.

This second solution has the added benefit that you can use a truly wimpy switch SW1 as LOAD1 and LOAD2 are directly driven through the MOSFETs.

As a side-note, you may need to add a reverse protection diode to protect the MOSFET from the inductive load.

Side-side note, since you have a microcontroller available, you could control the MOSFET from a microcontroller pin. This takes up an IO pin, but allows you to turn the other load on/off from code. This may or may not be desirable depending on your application.