Traffic shaping

Hello All,

i want to apply policy including Shared and Per IP for Example:

i have 8Mbps internet and 20 Users and i want to set shared 8Mbps and per IP 128Kbps in one policy

when 10 of users leaved what about for Other users will take all bandwidth or Fortigate will reserve The rest of bandwidth 128K for 10 users leaved before.

Many Thanks

Mohamed