how to randomize materials using material stylesheets

[marwan131]

i have little problem with randomizing material with instancing , i have a tree that has 2 materials 1 for bark and 1 for leaf the problem is to randomize a material with instancing is to apply the material after instancing and if i have multiple materials for each group or if i have multi geo with different materials and sub materials it will be a huge complex to randomize the materials and assigning them , i already tried material stylesheets but i failed to make it work , my main goal is to assign the materials for objects before instancing them.

in 3ds max vray there is a node called vray multisub tex and there is forest color i can apply them materials and sub materials to make sure to have different color per element per instance so i dont have to assign the materials after instancing i need only to assign the materials for objects before instancing  . im trying to achieve the same thing in houdini 

in

in this pic i have select_attribute i want to randomize it to have random number per instance if anyone can help me using material stylesheets and thank you.

 

 

 

 

random tree leaf before instancing.hipnc

 

 

EDIT: my idea is to have random value per element and per instance and most importantly to apply the materials before instancing and packing in case i have multi objects (buildings ,trees ) or in case i have multi material per object (tree: leaves and bark, or building : windows , walls, roof), i dont think this is possible to do without material stylesheets

Edited March 26, 2022 by marwan131
to explain my problem more clearly