Conditional Formatting within Tab Control

Hi,

I'm struggling to figure this one out.
I have an access 2010 form that has a tab control (3 of them)

I have created a text field named "TabCheck" that is placed outside the tab control.

I'm trying to create an expression or vba code to have that cell say "Check Other tabs" and possibly highlight it in yellow if "DateCreated" field from the other tabs are not null

The problem I run into is that when I do Me.fieldname, it only lets me pick fields from that same tab not fields on different tabs.

Thanks in advance