why is my timeline following a friend's timeline that i am not following?

i have removed the "follow" from certain friends due to very high activity on their plurks, however, it appears as if my timeline is still following theirs. based on the options on the page, it looks like it IS possible to friend someone and yet not follow their timeline. is this true? or am i misguided by what appears to be available options? i suppose i could unfriend them, but i'd like for them to be included in my filters, and i would like to remain the know with their timelines. i have tried following and then un-following them... this does clear all of their earlier plurks from my timeline.. but then when they submit new plurks, it appears on my timeline again. out of the 3 friends i have unfollowed, only 1 of them was fully successful from quite a while ago.