Madan sibs.
I think if you couldn't imagine them there for a weekend, and it would be strange, then that is likely your answer.
It is not wrong to not want a long-term relationship. But I would tell them that.
Consider it this way, if you did want a long-term relationship with someone, and you thought there was the chance of it, so you continued to spend time with someone because you liked them and then found out later they didn't want the same thing, after you had invested all that time? Would you be hurt?
And maybe neither of them are interested in that - then you can spend that time without feeling that pressure and you will enjoy time spent more. If they do want it though, they should know that's not something you're interested in - so they can make a decision with all the information.