Dynamic attributes within an object

Is there a way to show a dynamic list of attributes within an object? For example consider the following objects described by 2 different models belonging to 2 different teams:

"Box"                              "Box"
ID (id)                            ID (id)
Label (string)                     Recipient (string)
Contents (list:Contents)           Address 1 (string)
                                   Address 2 (string)
                                   City (string)
                                   State (string)
                                   ZIP (int)

Is there a way to put each "Box" object on a separate layer but have the "Box" object look as follows when both layers are selected?

"Box"
ID (id)
Label (string)
Contents (list:Contents)
Recipient (string)
Address 1 (string)
Address 2 (string)
City (string)
State (string)
ZIP (int)

I'm looking for a solution where each of my 2 teams only have to edit their own version (layer?) of the object and have the combined list automatically filter for unique values. Failing that duplication is fine as long as the object can hold all the values from the selected layers. Is this possible?