Boundary Conditions Degrees of Freedom

[fortoboy]

Hello, I was wondering if there was a way to control the degrees of freedom when we are applying boundary conditions. For example, if I wanted to design a uniaxial extension boundary condition, I only want to apply zero velocity to the x-component of the nodes I select.
Currently, I have to set the velocity components of all the selected nodes but in a uniaxial displacement experiment example pulling in the x-direction, I want the y & z components to be free to contract due to the poison effect.

Thank you,
Ron F