Should the rebels be asked to stop blowing things up while negotiations are taking place?

https://www.reuters.com/article/us-mideast-crisis-syria-idlib/shells-hit-syrias-idlib-as-rebels-prepare-for-assault-monitor-idUSKCN1LL0TF

It doesn't seem to me that the rebels can win by themselves, and that what they're doing is giving Mr. Assad and his allies an excuse to attack.  

Also, if the attacks do happen, a few ruined bridges won't stop them, although they will have to be rebuilt later by whomever decides to finance Syria's reconstruction.