I think I get it - not sure I'd do it. How will you synchronize multiple copies of the same table? I download and edit. You download and edit. Now what? Will propagating my and your changes over write one another? I'd be looking for a solution to the speed problem first.
Is it a network issue because even working with other Office files (Word, Excel) is very slow?
Is it a db issue because queries are not optimized? Too much use of aggregate functions across the network?
You are storing attachments in the db (not a good idea)?
etc. etc.
You really have 2 databases with the same name? I'd say that everybody having a complete local copy defeats the primary reasons for splitting in the first place.
The more we hear silence, the more we begin to think about our value in this universe.
Paraphrase of Professor Brian Cox.