I have a half-hotbar for exactly what you're suggesting. You just have to use the regular / commands to do it, though.
Just:
/target_group_member #
/useability Cure
/target_previous
# Ranges from 0 for F2 through 4 for F6. For me I just use my normal self-cure macro (below) although I believe /target_group_member can return you as a target. It might be an argument of 5 for it, don't remember since I've never had cause to use it for that purpose.
/useabilityontarget Cure <MyName>
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