I was just about to post this same solution - you just create a 3x3 swatch of the seamless tile, then bevel it and then cut out the middle tile of it.

I wrote a tut about seamless tiles. It wouldn't have worked for this bevel thing but you may find the thread interesting and it would have given you the hint on doing that cut out of the middle trick.

https://www.cartographersguild.com/s...ead.php?t=1373