What is the relationship between Natasha Milarose, Rico Tyrell and Heathcliff Flowen in Phantasy Star Online?

What relationship is there between the research institutes general chief Natasha Milarose and Deputy Commander Heathcliff Flowen?

Dialogue lines such as "Heathcliff... I never thought I would come across that name again... Fascinating..." suggest that she knows or to speak correctly lore wise knew him, but in what relation do they stand?

The same goes for Natasha and the principal's daughter Rico Tyrell, one of the last dialogues suggest that she knew her too. "Red... ... Reminds me of that girl..."

A diagram from the Ragol Report further fueled the possibility of a relation between Natasha and both Heathcliff and Rico.

To clarify the diagram, it displays a question mark on the relation between Natasha Milarose and Rico Tyrell as well as between Natasha Milarose and Heathcliff Flowen.

It would be great if anyone could shed some light on this.