Referring to different user numbers, user agnostic drive

Hi,

Two questions :

Is it possible to run something from one user number in another? As far as
I'm aware the answer is 'no'[1]. i.e. in 1B: run 1A:SUBMIT

Has anyone created a drive letter mapping that returns the same contents
regardless of user number?

I'm busy creating myself a development environment for an Amstrad PC/W
(and possibly also a Kaypro 10 I have at some point) using the rather
excellent CP/M Box from Habisoft.

This has two really useful features :

1) Built in UIDE hard disk support, so I don't need to eternally swap
virtual floppies.

2) An M: drive (which would normally be a RAM drive on a real Amstrad
PCW), which can optionally map directly to a local filesystem directory
but where *it always does this regardless of user number* !

2) in particular removes a huge amount of pain that would be present doing
the same in real hardware. It would be great to have this under actual
hardware too.

[1] Yes, I'm aware of the G switch in PIP. Surprisingly this isn't
included in the official PCW manuals, which are otherwise pretty decent.