Hi Hassan,
VC licenses is only needed on EX2300. On all other EX platforms the VC functionality is provided without need for further licensing.
Furthermore EX2200 and EX2300 can only do VC for up to 4 members. Rest of the EX series can do up to 10 members.
For EX2300 you would need a VC license for each member switch.
Hope this clarifies.