when you say multi-site what exactly do you mean ? Are the databases going to be created and master copies located at different sites and each site needs to keep these up to date ? or is the going to be one central repository of data and indices that all other sites access to maintain the up-to-dateness of data and indices ?
In the both cases as SRS indices are binary compatible (ie you can build indices on one O/S eg linux and use them on any other eg solaris, true64 51a etc), you should be able to set up a simple ftp check and move script that looks at the various sites in turn and whne data and indices are updated simply ftp's the required information from one site to the other. If you don't want to use prisma or write your own I'm sure there are either free-ware or commercial mirroring scripts that will do the job for you.
One thing to bear in mind is that you would need some mechanism to check that indexing had finished before moving the indices from one location to another.
If you need any more info let me know, also, a definition of multi-site as you need it would help.
PS If you want to take this offline that's ok.