How do you say these another way?
Let's catch up.
Let's catch up with him.
Let's catch up to the others.

Question

Answer

Depends on what you mean.

It can be like Matthew mentioned already, or it can be  the meaning of "let's keep up", "let's keep up with him", etc.

I think you're trying to say it in the sense of "let's not fall behind, let's keep up, let's get to the same place", or did you mean something else?

Answer

Lets go over whats happened

Answer

Let's meet up ==> let's catch up