AND OR question

Can I set up constraints to be AND OR. I have 4 tasks (A,B,C & D)

I want D to fire when the follwing criteria occur:

(A or B) and C.

I haven't managed to do this, as when I set up the OR constraint, all of the green lines turn to OR's as well.

Many thanks in advance for any help

Just off the top of my head...

Drop an empty sequence container onto the control-flow. Call it E

E executes when (A or B)|||Hi Jamie Yes, that works perfectly. Many thanks. By the way, do you know of any good sites for samples on using the expression language? BOL is a bit sparse. Specifically, I want to inspect an object variable to see if there is anything in it, as part of a costraint. Many thanks again