There is a very useful functionality in Sybyl, whereby
the user can "merge" a residue from one molecular
area, into another molecular area. The residue then
becomes a part of the latter moleculear area, without
deleting it. I wonder whether there is such a
functionality in PyMol.
As an example
Yes, the create command provide you with this ability, though at the end
of the process you end up with a new object.
create new_object, old_object1 | old_object2
In some cases, new_object can be the same name as either old_object1 or
old_object2:
create old_object1, old_object1 | old_object2
A