earth ground for a pool at a divorced location

i am putting a service to a deck area for a new pool and pump, there is an earth ground copper covered rod buried 10 feet which is 25 feet from the underground pipe i am splicing into for the pool power. can i splice the ground at that point essentially creating a ‘y’ between the subpanel in the garage and the breaker box i am installing at the pool and the earth ground in an effort to avoid rinning another 100 feet of solid copper ground wire from the pool breaker box all the way back to the earth ground rod. ty