use a layered shader. You can create a transparency map for one of the textures and then the second texture will show up in those transparent areas. There is a nice tutorial at https://www.mtmckinley.net/ (under "tutorials" then "other")
(I hope it's ok for me to post Mtmckinley's address here, sorry if I shouldn't have)
There can not be Good without Evil, so then it must be good to be Evil sometimes.
:tup: