It's possible....there are no client rulers in the lands of the Saba and I think the edges of India either. I don't really need to tell you how troublesome that can be, as Saba is REALLY hard to hold with anything but the best of the best family members. Unrest and distance from the capital coupled with high growth results in 40k riot cities.

That and you have poor choice in local garrison troops. You pretty much have to pay for a ferrying fleet and deplete the population of the southern Ptolomaic province if you want cheap garrison troops.