CO2.0: Need reference to parent and title on children of MG records [MG]

[jamieu]

Could be similar to how we handle parent on MPH children, but

• We need to differentiate when the parent is a MG or a MPH
• A child of a MG record can belong to many MG's (so the parent need to be an array)

Note: Once added we will need to add these values to the object page.

We should use the grouping element to discover membership as an object can be in many MGs (it can also be in a MPH as well).

A separate issue, but we should also refactor the MPH child records (members) to use the **grouping**element as well (I think we currently use parent).