Question Mergin 3 databases into 1 or into an exe file

[Shipper225]

Ok a bit of background, I've made 3 or 4 (could even be a dozen by now) databases in Access 2007 and instead of running them all as separate files I was wondering if there is a way to combine them all into one database or exe file. Now some of these are quite large databases so combining them by simply importing all their data into one file really (and I mean really) slows everything down. I've seen a program named shipping solutions that when opened runs 4 databases at once to supply it with all the information it uses.