My parents have an iMac (summer 2001) running OS X 10.4.11 and I gave them my PowerMac G5 Dual 1.8Ghz tower running OS X 10.4.11. I want to transfer their user accounts and add them to the existing accounts on my G5 tower. I was wondering if the Migration Assistant will transfer them to the G5 tower without wiping out the existing accounts? I need to keep the existing accounts intact for now.

What would be the easiest, safest way to do this?