Complex Filter Expression in PI Datalink

Greetings OSI Forums,

I have to combined a couple PI tags and filters into one Filter Expression.

''Some Tag' = "Closed"

''Some Tag' > .5

I need to combine these into one filter tag for datalink.  Since I am a C# programmer, I tried the obvious

''Some Tag' = "Closed" && 'Some Tag' > .5  and ''Some Tag' = "Closed" & 'Some Tag' > .5(no go)

Then

''Some Tag' = "Closed" and 'Some Tag' > .5 (no go)

Is there a way to make a multi tag filter expression where I have multiple conditions on individual tags?

Thanks Everyone.