Open files in left or right-most editor group in VS code

Is there a means to always open files chosen in VS Code's file explorer in a particular code editor group, say the left or right-most group?

I can use "Open to the side" (Ctrl-Enter) to open a file in a new group, to the right. Otherwise a file opens (in preview or otherwise) in the currently active group. This can be annoying, because often I'm working on a file in the active group, and want to refer to another file in a side group which I already have open (with another file in it), rather than a new side group. I have to activate the side group first, and then open the file I want to see: but I usually forget which group is active, and open the file I want to look at in place of the one I was editing...

I can use Ctrl-1, Ctrl-2 etc to switch to a group before opening a file: but I'd rather be able to use the file explorer as a GUI to explore files, without having to think: if I could "pin" the file explorer to a given editor group, it would be simpler.

What you can do is lock the group where your reference file is - for example on the right side - by clicking on the three dots within that group and then clicking Lock group, as shown:

This will make sure that no new files are opened in that group, but instead will be opened in your other group, on the left side.