Setting Texture Addressing Mode to Clamp instead of Wrap?

I couldn't seem to find information on this after digging through the forums. Can someone tell me how, if possible, I can set my textures to use a clamp texture addressing mode instead of wrap? I have some parts of my mesh using textures with alpha and the wrapping would create a very distinct line on the edges when it wraps the pixels and blends the completely transparent pixels with opaque ones. One work around I can think of is adjusting the image itself and shrinking things in, but then I'd have to do it enough to make sure the mipmaps will not display this issue too. If it possible to adjust the texture addressing mode, I much rather take this approach.

Thanks