BACKGROUND:
I am actually on my third iMac in one month (I have upgraded all the way to a 24" now). I have three folders on my time machine drive which is hooked to a 1TB external HD and respectively named iMac1, iMac2, iMac3, with iMac3 being the newest 24" folder. I just did a restore from a Time Machine backup on my brand new 24" at the start of OS X setup so I could have all my settings, programs, etc. be the same...the problem is, the restore that it implemented was from July 9, not the 21st so some things have changed.

PROBLEM:
Time machine will not read my older backups (so I can go back to a few hours ago and restore) because they are all in folder iMac2. I tried copying iMac2 to iMac3 (the newest folder), and it will not let me move files.

WHAT I NEED ANSWERED:
Long story short, I just want to move the files from my two older machines (iMac1 and iMac2) into the iMac3 folder to make them accessible to restore too.

Thanks for everyone's quick responses!