Sorry I'm such a cranky old fart.
The schematic below just uses a resistor to limit the current. You can work out the logic for full drive, reduced drive, and off.
Here's the
datasheet for the MOSFETs.
Mouser has them for $2.30 each. They are overkill, but you shouldn't have to heatsink them, as the one drawing 3 amps should dissipate less than 150mw. If you pick different ones, remember that the power dissipation will be I^2*Rds. So, lets say you pick one with Rds=0.2 ohms. The transistor will dissipate 1.8 watts, and will have a voltage drop of (0.2 ohms * 3 amps)=0.6 volts.
I'm sorry if I spoiled the learning experience of letting you do your own design. That would be better for you. You could use PNP switches, but, as I said earlier, you can't rely on beta to limit current. It changes from device to device, and it changes with temperature, and remember that the part that is wasting 4 volts is dissipating 8 watts. If that were one of your PNPs, it would get hot and be very unpredictable.
If you want to use saturating PNPs with resistor current limiting (as below), or a stable PNP current source, I could help you with that too. Just remember that a PNP drawing 3 amps is going to require a significant amount of base current, which is going to have to be supplied by an NPN, which needs to saturate. You might wind up needing more base drive for your NPNs than your logic gates can supply. The MOSFETs below won't switch very fast, but they require no steady-state gate current, which makes them very attractive for slow applications like this.
Edit:
I added flyback protection diodes to the electromagnets. If they are physically very close to each other, you may only need one diode.