Client glossaries in Excel contain alternate terms - how can I prepare those for import?

New to this group, so please forgive if this questions has been asked and answered a million times before... Our client keeps updating their glossaries to reflect changed terminology. Unfortunately, they are doing this in Excel by simply adding alternate, accepted translations into the same cell, separated by " / ".

Example - in Excel I have two cells:
"Controller" "Steuergerät / Steuerung"

Using MultiTerm Convert, we end up having the two alternate terms as translations for one source term which does not work if we want to do terminology checks.

Our termbase has about 1000 entries in 14 languages. Additions and updates come via Excel about once a month and changes happen with each update. I am trying to find a way where I don't have to identify all changes manually and then tinker with the TB to add those over and over again.

I know that when I export to Excel, those alternates are separated by "|", but this is a one-way street and doesn't help me the other way around.
Is there a simple way that the client can already do to prep the Excel to make the import easier?