question about markers

[Canadane]

/marking attack1 <t>
/marking attack2 <t>
etc

But you'd need to swap your target as your macro fires off with whatever delay you give it.

For enemies
You can try
/marking attack1 <e1>
/marking attack2 <e2>
/marking attack3 <e3>
/marking attack4 <e4>

Also, for the most part, people know who the healer is, a permanent mark doesn't help them not be bad, or whatever it is you're trying to help alleviate.