View TAGs of a block within a block

I have a 3D sign structure produced in CAD using Causeway PDS Sign software and I am having difficulty viewing the TAGs (or in CAD the ATTRIBUTES) of the sign face.

The way the program creates the structure is the sign is created as a block with attributes within it. Then the sign face block is used to produce the sign structure with post and foundations attached and again attributes attached to that.

I can only view the structure TAGs in Navigator and not the sign face. If I explode the block I loose the structure TAGS and I can then see the sign face TAGS.

Any help would be appreciated folks.

Thanks.