alternating parking and turn signals

I have a 2004 Chevy Colorado. That I have put switchback LEDs in the parking lights and turn signal lights I want to make the parking lights and turn signal lights alternate almost like the new mustangs tail lights do. Is there a way that I can wire them to alternate center the outside light without buying a module or anything like that.

I'm not familiar with the Mustangs but using normal LEDs or bulbs a circuit or module is required to kill the parkers whilst flashing.
Switchbacks should do that but I believe some don't.

I usually suggest exledusa.com's TPC modules (egm Version 2 or 3) unless people want to rewire so their flasher switch actuates relays that disconnect the respective parker(s) and connect the flasher can to the flasher(s), OR build their own module using a PICAXE 08 (~$3 plus voltage regulator & MOSFET).

Also not very good with electrical stuff. I know enough to get me in trouble.

thanks for the info, I looked at there stuff the one controller looks like it would work, The only thing is I need one power and two grounds. It is wire coming out with two pos and one ground. I emailed them and will see if it could be wired the opposite way like a relay.
Thanks again

As I recently wrote, LED controllers like the TPCs should be capable of switching relays instead. That assumes they can handle the (say) 250mA of a relay coil and the coil does not blow the TPC etc (ie, include a spike protection diode on the relay coil unless the TPC etc is known to handle relays) and that there is no dimming involved (reduced voltages or PWM will destroy relays if they do manage to work).
Hence signal or power inversion should be possible tho I'd consider alternate circuits else transistorised "inverters" rather than relays - at least for input signals and low-current outputs (like LEDs; relays are better for high-current bulbs & loads).