There is not a straight forward way that I know of no. However there is a workaround you can use.
Vector3.Scale: this method lets you scale the components of one vector by the components of the other.
So if you scaled your transforms position by a vector (1,0,1) then it would kill the Y value and leave the X and Z untouched.
However this then can look odd when skim reading your code later so personally I opted for the root of just writing extension methods for Transform that let me zero out the components individually.