Using $filter parameters with FUNCTIONV2 in Boomi REST API

Dear community, 

I am attempting to use a FunctionV2 call to GetResourceGroups from the NewEmploymentHandling screen, however I cannot work out how to use the $filter with this? 

Can anyone advise how I can use something like $filter=(ResourceId eq ‘RES01’) with this? or is it even possible. I have it working in Postman no problem with a Get call. 

Any help would be great. 

Dave