Inter Vlan configuration in switch

I have three switches (A,B, C) in the network. Each switch configured for vlan 10, vlan 20 and vlan 30. So the trunk port should carry all three vlans.

If i remove vlan 30 from the trunk port at switch C, vlan 30 users can not communicate with switches B and A vlan 30 users.

Ok if thats the case then you need to remove interface vlan 30 from the L3 switch configuration. This way communication for vlan 30 will only be allowed to other vlan 30 users.
However, another option is to use an acl on interface vlan 30, denying access to vlan 10 and 20.