How can i restrict number of rows from a dimension

Hi

I have following data in one of my dimension table.

Id                               display_name                        category

1                                 A                                                alpha

2                                 B                                                alpha

3                                 C                                                alpha

4                                  001                                           count

5                                  002                                           count

Now in my analysis view i want to see data with alpha category only. How can i implement this in OLAP schema. Neither i want to use database views nor I can change this table data. Can anybody help me? 

Thanks in advance,

Arun