Using Solver add-in with on cells that use the rand() function

I have a monte carlo simulation model and I need to set one of my parameters (service level) to be at least 95%. The problem is that, from what I know, when Solver runs, it tries different solutions, but because of RAND() function, the target cells keeps on changing all the time. Is there any way I could deal with this? Disable RAND() from changing temporarly? I tried to switch calculations to manual but that doesnt work because then the target cell does not update at all. I appreciate any help, thanks!