how to release specific degree of freedom in ANSYS Workbench?

I'm designing a truss which has 9 elements in ANSYS Workbench. since it is a truss, all of the elements are truss elements and can not tolerate momentum. I used LINK 188 element type for them. now, all I want is to define 2 of those elements as beams so that momentum can be transmitted between them(so we want 8 truss members and 2 beam members). but the important point is that only momentum about y axis must be transmitted, not momentum about z axis. I used BEAM 188 element type for these 2 members but it constraints all DOFs. any suggestion?!