Yes. Go to:
[User Control Panel] -> [Friends & Foes] -> [Manage foes] ->
[Add new foes:]Enter the username of the member you don't want to see his posts anymore. You will still see that the user posted something but the contents of the post won't be visible unless you allowed.
Alternatively, you could click on the user [profile] button at the bottom of his/her post. That will lead you to his/her profile. Then click on [Add foe]
Third option. Go to this link replacing [username] with the actual user you want to block.
ucp.php?i=zebra&mode=foes&add=usernameBest regards.