I think you can accomplish something simlar but not identical by doing the following:
- Create a security group in AD for each application and add the users to the corresponding groups
- Change the inventory setting so that the primary owner is based on the last logon (not the last 5-10 which is the default)
- Create a portal task for each of your apps and assign LDAP queries for each of the applications you want to make available (from #1)
- Change how often inventory scans happen to match your requirements of how fast users should get these apps advertised to them
- Change the interval of how often queries get re-calculated from every hour to every 15-30 minutes (depending on how many you have, this might be a heavy load on your Database server and/or domain controller) again to match your requirements of how fast users should get these apps advertised to them.
Good luck