The Blue Square Bet Premier play-off final will be an all-Welsh affair with Wrexham taking on Newport County at Wembley next Sunday.
FA Trophy winners Wrexham remained on course to complete a Wembley double by defeating Kidderminster 5-2 on aggregate after winning the second leg of the semi-final 3-1 at Aggborough.
Newport saw off Grimsby 1-0 at Rodney Parade to complete a 2-0 aggregate success and close within one win of a place in League Two next season.
Kidderminster, who finished runners-up to Mansfield in the table, almost levelled their tie against Wrexham early on when Michael Gash's glancing header hit the post.
However, Wrexham extended their overall advantage in the 29th minute when Brett Ormerod beat the Harriers' offside trap from Jay Harris' pass and lifted the ball over home keeper Daniel Lewis.
Kidderminster equalised in the 64th minute through Cheyenne Dunkley, the defender stabbing home from close range after his initial header from Kyle Storer's free-kick had been saved by Chris Maxwell.
Wrexham, who finished the regular season 13 points behind the Harriers in fifth place, were back in front five minutes later when Joe Clarke's low free-kick from the left flank deflected in off Lee Vaughan.
Gash drew a smart save from Maxwell as the hosts attempted to hit back, but the Dragons sealed the win with five minutes remaining through Neil Ashton's penalty after Adrian Cieslewicz had been felled by Josh Gowling.
Newport took command against the Mariners in the 31st minute with the only goal of the game when Christian Jolley latched on to Alex Gilbey's pass and found the net with a low, angled drive.
Grimsby rarely looked like getting back into the contest and both Michael Flynn and Gilbey spurned good chances to extend Newport's advantage after the break, while Danny Crow had a goal disallowed.