Dynamic Lookup Field

Hi

I am trying to overcome a mismatch of field type error with a dynamic lookup field

I have an organisation and a people form. The organisation name field in the organisation form is a strong type.

In the people form I have a lookup to the organisation name field. This is what determines which people are employees of different organisations. This lookup field in Bigint.

In the organisation form I have a mulilookup field to look up and record people that are employees of organisations. The set filter is used to try and only present me with those people that have a link to the organisation name value on the current record.

It doesn't work though because these two fields are of a different type. Any ideas how I can make this work?