Row Level Security and Roles

I have a table called Cost_Centre, within that table I have a column called UPN which is the UPN of the cost_Centre manager. This column can have multiple values in it. For example I have placed the following in the UPN colum :

[email protected]

[email protected]

[email protected]; [email protected]

[email protected]

If I login as [email protected] - I want to only see rows that Mark can see . I have created a role and added a filter on the UPN column - and was hoping to restrict rows based on the UPN value in the column.

This works when I only have a single user in the UPN column - but sometimes I need more than one person :

When logged in as Mark this works with [email protected] as the only value in the UPN column for the row :

=dim_CostCentre[UPN] = USERPRINCIPALNAME()

So I have tried this with the string with multiple users  - and cannot make it work :

IF(CONTAINS('dim_CostCentre',dim_CostCentre[UPN],USERPRINCIPALNAME())

When logged in as Mark abc.com no rows are visible. I think the contains is working on the column and not the row. Any ideas on how I can make this work.

Thanks