Stereo Power Question

[foosed]

I was wondering if there was any way that i could somehow wire my stereo to stay on until the doors open after you shut the key off, like the newer vehicles do. I was thinking i could tap into the dome light switches on the door, but that would do just the opposite wouldnt it? My truck is a 72 k10 by the way. Just an idea i have been tossin around in my head, any input would be appreciated