Adding checkers for a specific test

Hi,

I need to verify sequence of data going out of a port to match a particular pattern…and this pattern is different for different sequences I am running… I want the test to pass/fail depending on pattern matching…

In my case I have 128 bit data coming out of data_port… and the data in data port should match particular pattern say all a’s at cycle 1 and all b’s cycle2 and so on…

and this pattern is different in different sequences…

I should read this data written when the valid signal is high for one clock cycle…
and this data i need to store in queue…

I tried with assertions but it will check for both sequences… i want to check only when particular sequence is called…

is it possible to define some kind of checkers in sequence class so that it will check only when that particular seq is called?

please help if there is any other way to do that…