Create/split metacontacts via the keyboard
There is no way to create metacontacts via the keyboard.
Perhaps a quick way to achieve this would be a context menu item on contacts, "Group all contacts with this name." Then, if I have 5 contacts named Nolan, highlight one and click this option, all similarly-named contacts are grouped under this metacontact. A "Detach from metacontact" option could then be added to all group members to allow breaking each JID out of the group later.
Another option would be a "manage metacontacts" dialog similarly to "manage groups," which is almost the exact same workflow, only each contact would have a dropdown item for the metacontact, and there'd still need to be a way to create the contact. So maybe a combobox text field pre-populated with all existing metacontacts. This breaks the requirement that all MCs have the name name and is probably a better solution.