Zanthor makes a good point. What is it you are trying to do exactly? If you are trying to lets say use 2 spells for a single character its not possible unless said spells do not trigger a GCD, if they do not then put them on a single macro and they will be activated. There is no point in pressing 2 buttons if they are on a GCD if one is not again putting it on a macro makes more sense, now if you are trying to do it for multiple char's like you have 7 on one char and 8 on the second char why not just put it on same button for both of them? If you use one of the programs mention to accomplish this then really whats the point of not putting it on the same button if your talking about 2 char's unless you are using a modifier in which case you are not technically pushing a single button since you are going to have to press 1 then shift+1. Still confused as to what you are trying to do.

For my guys I have 2 for dps macro but it is not use by lets say the tank which only uses 6-0 for tanking skills so I will press 2 and 6-0 together at any given time, but if I wanted to do as your doing then I would just bind my tank macro to 2 and keep my dps macro's on 2 as well. But this does not always work well, really for the most part you want to have those separated, what your trying to do would not work since every time you press 7 it would say press 7 and 8 at the same time which is the same thing as having all your abilities on 7 in a macro format.