I don't know whether it is useful, but I've just made a healing macro that "If you target an enemy or nothing, cast Cure on a tank(<2>). Otherwise cast Cure on a target".

/merror off
/mlock
/focustarget <f>
/focustarget <t>
/ta <2>
/ta <f>
/tle
/tlt
/tle
/tlt
/ac "Cure" <t>
/ta <f>
/focustarget <f>
/micon "Cure"

I also made the following macro formerly. But it doesn't work now becouse of a disorder of "/focustarget" command; focustarget cannot be canceled by reuse.

/merror off
/mlock
/focustarget <f>
/focustarget <le>
/focustarget <t>
/ac "Cure" <f>
/ac "Cure" <2>
/focustarget <f>