Simple, create shortcuts from the main admin account & copy/send those to the user accounts of each family member. I'd send one to desktop, & possibly also one to start menu on each account. Each user will by default save their files in their own account area & their separate settings will also be saved into the individual user account.
eg: default save location: C:\Documents and Settings\"your account name"\Shared

LW preferences folder with individual settings saved for each user: C:/Documents And Settings/your_username/Application Data/limewire