Lua dissector organization

In the "Enabled Protocols" dialog some protocols have trees of sub-protocols. How is this organization defined, specifically when writing a protocol dissector in Lua?

For example, I have dissectors defined in this way in %APPDATA%\Wireshark\plugins:

• myproto.lua: MyProto
• myprotomsg1.lua: MyProtoMsg1
• myprotomsg2.lua: MyProtoMsg2

MyProto adds itself in to wtap_encap in USER0 and creates a DissectorTable "myprotomsgs", and each subdissector adds itself to that table.

When I go to the Enabled Protocols dialog, I see:

• MyProto
• MyProtoMsg1
• MyProtoMsg2

when I expect to see

• MyProto
•      MyProtoMsg1
•      MyProtoMsg2

Is this possible using Lua?