Stupid question, but have you tried giving them the "solid" behavior?
Also, could add "Enemy - on collision with - Enemy - Rotate 10 degrees" or something along those lines.
I'm still an amateur with Construct so forgive me if I'm wrong <img src="smileys/smiley2.gif" border="0" align="middle" />
Edit: downloaded and run the capx, noticed you've already done that... Will keep trying :)