Eagle is placing thermal reliefs around small SMT IC pins - how do I edit them?
It's not the thermal relief causing those connections, it's your ground plane. Just keep it away from areas where you don't want it. 

You can either draw the ground plane polygon(s) to avoid the area, or put a rectangle over it in the 'Restrict' layer.



ETA: Eagle version 6.0 and above has the option of using a polygon with 'cutout' pour instead, which avoids potential DRC errors in the restricted area. Thanks to Tom Carpenter for pointing this out.