It is possible. But you need to setup the texture layering correct:
1 BaseTexture
2 DetailTexture
3+4 first overblend texture with its "alphamap"
5+6 second overblend texture with its alphamap
7+8 third overblend texture with its alphamap
when I remember correctly, the uneven is your texture you want to have drawn and the even ones is the blend mask (could be vice versa, please don't nail me on that). But you need to set the blend masks blend correctly as well as have the correct load flat. With the mask above, you would need to use multiply blend, where white means "do nothing" and black removes the original texture completely. And you would need a texture loading flag of 1 or similar, but it MUST NOT include the MASK flag or the black parts will disappear which breaks the blending.
1 BaseTexture
2 DetailTexture
3+4 first overblend texture with its "alphamap"
5+6 second overblend texture with its alphamap
7+8 third overblend texture with its alphamap
when I remember correctly, the uneven is your texture you want to have drawn and the even ones is the blend mask (could be vice versa, please don't nail me on that). But you need to set the blend masks blend correctly as well as have the correct load flat. With the mask above, you would need to use multiply blend, where white means "do nothing" and black removes the original texture completely. And you would need a texture loading flag of 1 or similar, but it MUST NOT include the MASK flag or the black parts will disappear which breaks the blending.