Look up function inside IF condition visibility - SSRS

I have a SSRS report with one tablix and i want to hide the tablix based on a condition. I am using two datasets there. The tablix contains dataset1 records. I want to check the dataset2 with Pno and if then only need to display that Pno in tablix. Dataset1
Pno Group 1 A 2 S 3 D 4 F Dataset2 Pno Supply Demand Group 1 A 3 D 5 B 6 R Now I want to display only Pno Group 1 A 3 D I am using the following condition.

=IIF(Lookup(Fields!Group.Value, Fields!Pno.Value, Fields!Pno.value, "Dataset2"), True, False)

But it doesn't filter the records. Can anyone help me to solve this? Thanks in advance...