Garageband Sequencer

I have a midi keyboard and am able to set different kits in garageband, but its only single notes. What I am looking to do it take multi-track loop or even just loops and set them to the keyboard. I want to push the key and have the loop play continuously until I release it, while doing this I should easily be able to keep the same BPM with one hand and also be able to spin some vinyl... also it it possible to change the pitch by going up and down on the keys? I have done something similar with this at school with Digital Performer and a plugin called Mach 5 but cant seem to figure out garageband. I have checked youtube and the apple site for help but they do not get specific enough for my question.