How To Write Not Equal To Effectively For Mtrl Group In Release Strategy For Purchase Order

We want to use material group in release strategy for purchase orders. There are total material 52 groups.

Three groups to be released by one user and remaining group purchase orders will be released by another users.

For 1st user the three groups have been written in classification BUT we are facing problem in writing 'Not Equal To'

effectively for the 2nd user. We want to write the classification as Mtrl Group: <> the 3 groups of the 1st user OR

Mtrl Group: <> space.

Is it possible ? If yes, how. Anybody if aware, please answer.

Thanks in advance,

PVish