Should I say something if I do not want a joint birthday celebration with some one I am not close to?

My birthday is important to me. I know some people don't feel that way but I do. In fact it is one of the few events that I care about.

For some years some friends came up with the idea that they can celebrate my birthday with another girl's birthday together. They would pick a date that's neither her birth date nor mine. It's convenient to them you see.

Money isn't the problem. I am only asking for a meal together and we are all working adults.

However they do it year after year and I am getting weary. The other girl didn't mind because she doesn't really care about birthdays. Honestly I don't know nor like that girl much. Year after year I have to pretend I am alright with it. I mean, who am I to spoil their plans when they bothered to include me?

I remember telling one of the guys abt this but he doesn't seem to understand. I don't know what to say to get it thru.

What would you reply when they say 'I don't see why you're so glum abt it. Celebrating together is fun!' and they don't understand it's not fun to me?

Oh by the way, even though it is a joint birthday, they would pick things leaning toward the other girl's preference, cos well, I am the easy going one so they feel they don't have to ask me.