Imprecise number selection in Messages

Nexus S i9023, stock Android 2.3.6.
I have many contacts which have more than one number. The number displayed in the top left corner keeps changing and I have to select the right one every time to be sure the reply is sent to the correct one. A few times I have left it as-is and even if the displayed number is wrong it replies to the correct one.

Please fix this issue somehow, maybe even creating separate conversations for different numbers.
Love this application, hope it gets even better soon. Keep it up
B-)

We're looking into this issue now. Thanks for the feedback

Any news on this issue? Sometimes I keep sending messages to the wrong number even if the correct one is selected, I've already wasted different euros (I have free sms to Vodafone but they are sent to the other number)
Even on the phone it shows they have been sent on the Vodafone contact, but the person receives them on the other phone!

Sorry to bother you, I see you are working hard for this great software. Just wanted to know if it's not that hard to work around this problem and add a few details i've discovered recently!
Separate conversations would be great too, if they can simplify your work