Question about using Airport with Ext HD via USB port

[WizardHunt]

I own a airport which I use to connect my mac mini. I will be getting a new iMac soon and would like to know what is the best way to have a Time Machine drive hooked up so it will back up both Macs.

Option 1 : Should I manually hook up a external HD for Time Machine to use on the back of the Mac Mini. And on the iMac the same with another external HD for Time Machine. This way they will have their own Time Machine.

Option 2: Could I Hook up a larger HD Drive like a 1 TB external drive to the airport's USB connection in the back of the airport to work as a Time Machine for both machines.

If I use option 2, will that slow down the performance of the network if the time machine is constantly backing up each hour?

So what is the best way to handle this? Any suggestions would be appreciated and would love to hear from anyone who has done this?

Thanks in advance.

[flopticalcube]

I assume you have an Airport Extreme Base Station (since the Express cannot use a HD). I would go for the first option of a HD on each machine. Its much faster than using an Airdisk and you don't have a single point of failure. If you have one drive and it fails, both backups are toast.

[WizardHunt]

I assume you have an Airport Extreme Base Station (since the Express cannot use a HD). I would go for the first option of a HD on each machine. Its much faster than using an Airdisk and you don't have a single point of failure. If you have one drive and it fails, both backups are toast.

Yes I have the AEBS. I thought it would be better to use a Time Machine for each Mac but I wanted to get confirmation first. Thanks.