RPL help - If value is in table, do this

Hey. Anyone know whether theres any kind of RPL if statement on whether a data source value exists in another data sources column?

Scenario

I’ve got a dynamic variable called REF with the value of ABC123 and my customers email address is test@test.com

I have a supplemental table in my data sources that looks like so

EMAIL                BKGREF

test@test.com   ABC1

test@test.com   ABC12

test@test.com   ABC123

I want to try and say if 'REF' is in that BKGREF column, do this, else do that.

Referencing that column via ${sourcename.BKGREF} only considers the first row, whereas I need to try to reference the whole column