Accessing public events within nested UserControls?

Ok,

I hope I can convey what I'm trying to do....

I have a single UserControl (uc1) that is comprised of 6 other UserControls (ucSub1, ucSub2...).

UserControls ucSub1 - ucSub6 contain various controls, among them...a ComboBox. Each combobox needs to be populated via a DataTable utilizing the "DisplayMember" and "ValueMember" properties.

uc1 is created dynamically and can have up to 12 instances. Each instance is placed on a dynamically created TabPage of a TabControl.
12 uc's = 12 tabpages.

Each ucSub? has within it's code-behind the following statement:      Public Event LoadCombos()

At this point, uc1 has no code-behind code.

I'm pretty sure at some point I need to add an event using the "AddHandler" that will fire when a uc? control is created.

Here is my question:

What is the best way to code this so that when a uc? control is added, all the ComboBoxes of each ucSub? is populated?