Hi Prasetyatama,
Is that a plain MPLS network or L3VPN setup?.
If the setup is L3VPN (assuming R1 and R6 as PE devices), you can either use mGRE or multipoint LSP as P-tunnel. Incase of mGRE, you need to enable multicast on all core devices and incase of MP-LSP, you need mLDP feature supported. Below are few link about MVPN over mGRE or Label switched Multicast,
http://www.cisco.com/en/US/tech/tk828/tech_digest09186a00801a64a3.html
http://www.cisco.com/en/US/docs/ios-xml/ios/ipmulti_lsm/configuration/15-1s/imc-lsm-15-1s-book.pdf
On a plain MPLS network, you need to enable multicast on all routers and it is not different from multicast over non-mpls core network. Curently, LSM is not supported for this scenario.
HTH,
Nagendra