SQL Code Help Please

I have the following query producing a recordset drawn from 2 tables.

SELECT
*
FROM
dbo.[qry_HorsesANDRidersAssociations]
Group By ClientID, HorseID, HorseName
UNION ALL
SELECT * FROM 
dbo.[qry_HorsesRidersHaveCompeted]
Group BY ClientID, HorseID, HorseName

It produces a list of horses that a rider "wants" to have associated on their account and also a list of horses they have actually ridden.

I have been asked for a facility to hide horses from a riders account - which is more applicable to the ones they have actually ridden rather than associated (as they can easily remove this association)

A new table tblHideHorse has been created with HorseID and ClientID along with HorseHideID (identity)

How can I combine this into the above query to produce the list minus the horses they select to not show?

I know it is something along the lines of

where clientid not in (select ClientID from tblHideHorse) but im afraid that is the limit of my knowledge.


Thanks in advance

MSSQL server 2014