For Repose, you can use a macro such as this if you'd like.

/ac "Target Forward"
/wait 1
/ac "Repose" <t>

Assuming there's more than one enemy, and you have one of those enemies targeted. This macro will target the next closest enemy onscreen, and cast Repose on it after one second.

You can try taking out the /wait command, I don't think its necessary, haven't personally tested this but it can be a bit glicthy without the /wait command. If you test it, and it runs fine without it, then you can just leave it out to be a little more faster.

You can then also add in a Mark Target command line at the end of this and mark it as one of the Ignores to let your party know not to hit it.