without Ogre/Ray your options are a bit limited. Without getting into obscure options (Flygon, Giratina-O, Ho-Oh, etc), some options include:
Mega Salamence is probably one of your most reliable checks. Intimidate can help nullify physical groudon. Special Groudon is also not very threatening if its Eruption has been weakened.
The other common answer is Skill Swapping levitate onto your own Groudon, but that requires some maneuvering and isn't straightforward. Gengar can do this quickly due to its base 110 speed, but Cresselia will require Speed control (thankfully it has the bulk to do so)
Yveltal, Kyurem-W, Landorus-T and Kangaskhan can pressure Groudon fairly hard.