It is not possible to copy & -> &

What causes this issue?

You want to copy group &V1& to &V2& using a suffix. The generated copy,
however, is not unique. At least one subgroup appears in &V2& more than
once.

System Response

The system does not allow you to copy group &V1& to &V2& using a
suffix.

How to fix this error?

Change the reference so that no groups are copied more than once, or
copy only subtrees, which remain unique during copying. Copying is not
possible if there is at least one group in a reference that differs
from another group in the reference only by suffix (for example,
XXXXXXXXXX and XXXXXXXXXX.YYYY or XXXXXXXXXX.YYYY and XXXXXXXXXX.ZZZZ).
The system displays the selected reference and the copy. Groups that
appear more than once are highlighted in color in the "Copy" column.
Such groups are also given a sequential number. Groups appearing more
than once are each assigned to the same number.
You can use the sort function to quickly determine the groups that
appear more than once.

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