How to cut an object using a plane

I am trying to resize some door, window, and cabinet objects in Sketchup Go. (They are all home-brew, not downloaded from the Warehouse.)

Using the resize tool (“S”) will not work, because it resizes everything, including stiles, rails, and frame pieces in the door or window. If I need to reduce the width of a door by 4 inches, I don’t want stiles, rails, trim, attached hardware, etc. to get laterally compressed. I really want to just take a slice out of the middle of the door without affecting its edges.

All I have figured out so far is to make sure the objects are solid (not always easy), insert a “cutter” (3D rectangle, to be solid) into the object to be adjusted, subtract the cutter and the contained chunk of object, explode the object so I can move the two halves independently, slide them back together, and hope that the result will give me a solid group in case I need to do more chopping.

It gets even more complicated when I need to widen an object – do this cutting operation on two or more copies of the object, so I can Frankenstein the two edge portions of one onto the center portion of the other.

I’m hoping there is an easier way to do this – basically excising part of the middle of an object without affecting the edges. It would be nice to be able to use 2D rectangles as cutters, but I haven’t found a way to do that.

Can anyone send me a link to a video or other instructions on how to accomplish this in a less chancy and cumbersome way? Keep in mind that I’m using SU Go, so no access to extensions or plugins.

Enter the group for editing, double click, then use a Left to right selection fence to only select the parts you want to move, move them. The exit out of the group. Usually no chopping/exploding/frankensteining needed.
GIF 10-02-2024 6-45-00 PM
But if you give us an example model we can be more specific.

Just getting back to this now… THAT IS PRECISELY WHAT I NEED!!! Thank you!

It’s not needed in this case as moving the correct selection is much faster.
But “intersect faces” does something like that and is very useful in other cases.