Custom fields and single/multiple entry

Hi,

I’ve had two requests from different groups that work with a particular
database system here. They each want a custom field which links to ids
in this other database. All nice and easy to do.

The problem is, that one of them wants the CF to be single entry, and
the other one wants the CF to be multiple entry.

Is there a sensible way to achieve this, other than having two otherwise
identical custom fields, differing only in whether they are single or
multiple entry?

Thanks,

Tim

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