If I understand your request, you want to put everyone into a single table but then want only subsets of that table to appear on certain layouts customized for that group.
You can set two different script triggers to help with that: OnLayoutEnter and OnModeChange.
With both, you can perform a script that constrains the current found set to only records of the specified group. OnLayoutEnter might just perform a find for all records of a given group at your option. But for OnModeChange, you want to set it so that you get that constrain each time the window enters find mode. This allows the user to perform finds for records and then their results are automatically filtered down to just those of the permitted subset.
You might also set up one table for all contact info--such as names and a different related table used only to record relevant details specific to one sub group.