Its in the healbot options in the Bars options. Select the right Skin and Frame
Skins - Frames - Bars - Select the "Visibility" button - and then de-select Group 5 in the "include groups" around the centre of panel.
Hope that helps
Given the format of the bar is different it might be another frame addon or the default UI.
If you are using z-perl, x-perl or something similar look at the frame setups.
Another possiblity is the default ui - check that - WOW options - Interface - Combat - "Target of Target" is not ticked.
Hope that helps.