astrophotography - Stack star photos without trails but WITH sharp foreground?

I have a Nikon D5100 and a Tokina 11-16mm f/2.8

I want to stack multiple star pictures while also keeping some interesting foreground for context. I don't want star trails though.

I understand that given my camera is fixed with the foreground, without some smart software process that identifies the foreground and the stars and only rotates and stacks the stars this doesn't seem plausible. [The stars are obviously moving relative to the foreground.]

The question is: Are there software tools that'll make this work? Or perhaps some clever blending technique?