Conditional Logic - combine ALL and ANY

I'm trying to create a condition whereby a field is displayed if there is a combination of AND and OR logic (GF equivalent of All and Any)
So for example display field3 if field1 = A and field2 = B or C

I can't work out how to achieve this is GF because my only options appear to be ALL (ie. if condition-1 is true AND condition-2 is true AND condition-3 is true .... condition-n)
or ANY (ie. condition-1 is true OR condition-2 is true OR condition-3 is true .... condition-n)

I need to be able to to resolve the issue whereby (condition-1 is true AND (condition-2 is true OR condition-3 is true))

Can someone please let me know how to solve this in GF as it is a very standard and straightforward type of conditional logic to resolve.

Many thanks
Rob

Not an expert, But could you not do that with a hidden field. Merging the content of two fields into one, and then using a conditional logic on the value of that merged field

Mark