Both are level 65 group healing spells.
Yes you can chain cast them, once.
Cast one of them, and then cast the second before the first one refreshes. But you then have to wait for the first one to refresh.
It takes 3 seconds to cast and about a 1 second wait to cast other spells.
But they have 30 second recast timers.
If you're group healing, best to have both by far.