Should fostered siblings visit each other?

I'm fostering one and a friend's fostering the other of a pair of adult sister cats that were dumped by their owner. They both seem to be doing "okay" -- hers maybe a little better. Mine, though adjusting - eating, hissing at my cats less -- still seems depressed. I notice particularly that she never purrs, not even when being stroked.
Our ultimate goal is to find a home where the sisters can be together again? Meanwhile, would it be beneficial or confusing to let them see each other?

Thanks!

Because cats need their routines to feel secure, I'mm afraid letting them visit might disrupt all the "settling in" they may have done up 'til now. One or both of them is going to have to be taken our of their newly familiar area - that's stressful in and of itself.

The visit might not go well because they may have begun to forget one another. A home together would be ideal - if they've fogotten, they'll remember soon enough in their new, permanent environment.

I can see it oth ways but depending on the temperment of the cats, I'd stay with the status quo.

I wouldn't, especially if one is having a hard time adjusting, you would need to go through that each time they see each other

What about swapping blankets so they can smell each other? It'd be less stressful for them than having to pack one up, and still help maintain their familiarity and comfort with each other.