Allow multiple values to BDC Column

I have added a column called Customer to my documents library, this is a business data column.

What I want to do is relate a 开发者_开发百科document to multiple customers by entering customer codes into this box.

Currently I can add 'FLC' for example, but I want to put 'FLC, MFT, SAL' for a specified document as it relates to many customers.

Any ideas?

Cheers, Albert

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You might need to develop a Custom Field Control derived from the BDC column to make this Possible.

I dont see any out of the Box Solution that is available to achieve what you want.