Hi,

We were solving this problem over the e-mails. I am posting here the answer just for other's reference.

The only way how to achieve this is to modify the filter web part and its code behind get the values added and truncate them field by field and set them individually.

For example:
<displayName>;<fieldName>:(A [A|B TO A|B] [A|C TO A|C]) will be separated to:

<fieldName>: A <fieldName>: [A|B TO A|B] <fieldName>: [A|C TO A|C]

Best regards,
Juraj Ondrus