3.5mm jack to phono from laptop to a free INPUT on amp 1. Then, if the same amp has a record OUT, then run an ordinary Male to Male phono lead from that, to a free aux IN on amp 2. Then on amp 1, Switch record selector to the INPUT you have your laptop connected to. Then, on amp 2, select the input you have plugged it into. Adjust volumes accordingly. (OR, just run two phono's from record out, to record in on both amps - if you have the luxury of having two identical amps) BUT remember, just as jsmithepa said, the stereo phasing may be slightly out. But i run a similar setup with my two Technics SUV-670's and i have not had a problem.
Good luck!