How can I combine selection criteria??

I would like to select objects which are on a specific layer AND in a certain group at the same time.

How could I do that?

I only found bpy.ops.object.select_grouped(), where I can define 1 selection criterion.

Many thanks for help!

import bpy

grp =["Group"]
layer_num = 0
sce = bpy.context.scene

# Deselect everything

# Enable target layer (optional)
sce.layers = [False] * 20
sce.layers[layer_num] = True

found = False
for ob in grp.objects:
    if ob.layers[layer_num]:
        print( = True
        # Make one object active
        if not found:
            found = True
   = ob