Party Raise Question

[Unarmed]

What is the minimum someone needs to re-raise allin where I am allowed to re-re-raise?

CO 2k
Button 8k
SB 1k
BB 1k

Blinds 50/100

CO calls 100
I raise to x
SB pushes
BB folds (don't ask why I have 3 players in this example) [img]/images/graemlins/grin.gif[/img]

What is the max value x where CO can call and I can put him all in? I know if x = 800 for example, I am not given the option to re-re-raise when CO smooth calls.

Does that make sense to anyone? [img]/images/graemlins/confused.gif[/img]