replace components

Hi all,

There are 10 parts in an assembly that are all the same part. I want to replace 6 of them and leave the other 4 as they are. However, when I select the 6 parts with ctrl in my component tree and replace them, the other 4 get replaced too. 

Any way how i can fix this problem, or do i have to delete the 6 parts en import the new component 6 times?

Thanks in advance

SolidworksGeneral