Pan Half a Texture

How can I horizontally pan half of this texture? I want to pan half the texture and then switch so that the whole texture pans, and switch again so that only the second half pans. I’m sure there’s a way to do this with texcoord but can’t figure it out.

use Lerp function. with it you can interpolate between static and moving UVs by masks. masks also can be created with UVs.

I want to split the texture in two, so that the first half will keep panning through, then be able to pan the whole texture, then just the second half. It’s to give the imression that a series of parallax layers of scenery are moving on to a different part of the scene.