Unown G and Pokemon Tools

[Donezator]

Sorry if this is already answered somewhere, but my question is : Can I attach Unown G to a Dialga G which already has a Pokemon Tool Card on it? There is nothing restraining it from doing so on the card, though I just wanted to be sure. Thanks¬

Donezator

 

[PokePop]

There is something restraining it.
The Rule Book.
The text doesn't have to be on the card. It says so in the rule book, under Pokemon Tools.