In sellacious, you can hide the out of stock products from the frontend. Go to Sellacious Backend > Settings > Global Configuration > Frontend Display options. Set Hide out of stock products as Yes.
However, I have a question here. What do you mean by Unavailable products?
In sellacious, if the product is not available for sale, you can disable the listing from the product catalog.
If you can explain this to me more, maybe I can help.