If they're the stock batteries, then I wouldn't charge above 1C each unless someone can show where they list a higher rating.
Theoretically, your parallel charging current is just your single battery current times the number of batteries, so 2.2A x n
However, parallel charging relies on all the batteries being at the same state of charge. I think the risk is that if there's a difference in voltage, the lowest one gets charged at a high rate by all the others.
Even if you're confident they're all at the same voltage, +/- 0.1V then, for safety, I'd charge at 2A per battery just to give you some margin.