Permissions array operators: Check if array column contains value

I am currently testing Hasura for use in a productive system and am quite impressed, good work!

Unfortunately, I have not yet been able to realise an auhtorisation use case, the following scenario:

_A customer has several divisions, users can belong to several divisions and have several different roles there.
To map this, there is a table userDivisionRoles in the database with the columns userId, divisionId and roles (an array of the enum DivisionRole)._

I would like to check for incoming requests in the table userDivisionRoles:
- userId = X-Hasura-User-Id
- divisionId = X-Hasura Division-Id
- roles: Contains X-Hasura-Role / X-Hasura-Default-Role (= user has the appropriate role in the division).

So basically what is needed is an array operator "contains" that checks whether a certain value (right side) is contained in a column of type array (left side).

Does such an operator exist and have I overlooked it, or is this simply not possible so far?
How could this be modelled instead?

Thank you very much!