Time-out for Cookie

[zetetic]

The "Time-out for cookie" option in vBulletin settings is defined as:

This is the time in seconds that a user must remain inactive before any unread posts are marked read. This setting also controls how long a user will remain on Who's Online after their last activity.

So, I have a couple users who want this time-out set at an hour because they say the default setting (15 minutes) doesn't give them enough time to read all the new posts before they get marked read.

The problem is the fact that it's tied into the Who's Online list, which gets screwed up because it retains user info for an hour.

Is it possible to split the Who's Online list off so it doesn't use the same setting as the "mark posts read" function?