Naming 3rd kid differently.

So this is the year we plan to TTC again, and baby names are already filling my mind. Just one problem. Our two children now, both of their names start with an "A"
Not purposely, but because I fell in love with both of those names. 
The third one, the names I love don't start with an A. But I've been told the next one HAS to start with an A as well or they'll feel left out. What's your opinion? Can I change up the letter, or am I in too deep?