I like to keep my heals separate - mostly because I don't need much. You will be killing things before they get to you or shortly thereafter. Try starting out with a separate macro like:

/cast [target=Hermy] Renew

It will allow the character to cast the heal without ever switching targets. I use my second row of hotkeys with the alt modifier (bartender is part of my ui), so it's just a quick alt+1 etc to heal any given target. Others here use their F keys. You can set up the buttons in various combinations as well. For example, pressing alt+1 or F1 could cause your main to nuke and second to heal the first guy, or have them heal each other or themselves - you see where I'm going. Placing the macros on various keys gives you a lot of fexibility.

One last note: I beleive you can bind the macro to a key as well but I forget how. You can check with the sharper tacks in the macro forum