Assign role to user based on multiple mail column

Greeting guys , 

i have a quick question , my client changed his extraction of data he wants to allow the user to see only offer that have access to it. 

to get this information i have a column name "access". 

The problem "access" column have a list of emails ! 

Example :   Access  = "[[email protected]] , [[email protected]]"  as you can see the column access could have more than 1 email. 

any trick i can use in the RLS ? 

in the previous version of the data it was simple there was only 1 mail in the column  so all i need to use the USERPRINCIPALNAME() but now the column contain more than 1 mail ! 

Thanks all in advance