I fear not, no. Unless you move any characters you don't want to lose to another realm (that does have additional realms connected to it) and recreate all the other characters there, all you've got left for the time being is hoping that there will come a point in the future where your realm will get connected to one or more other realms.

When my significant other, a good friend of ours and myself decided to move to a new realm last year, we made a list of all the realms that are connected to others, and then had a look around on each one to be able to compare them (counting the total number of auctions that are up on the auction house, checking prices and availability of particular items, seeing how busy Stormwind and Orgrimmar are certain hours of the day, things like that). That's how we settled on a realm that has two additional realms connected to it. Not because we actually expect to create 33 characters per account (though I'm closer than I thought I'd get ), but because (as I mentioned earlier) we quite like having one realm for the Alliance, one realm for the Horde, and one realm for any additional characters.

When we did this, I started out by creating characters on the new realms and boosting them with a 'main' that was still on the old realm, as you can invite your own characters into parties cross-realm as well, after all. You just can't trade with them at that point, but you can easily get a little starter gold by caging pets and selling them on the new realm's auction house, or taking a new lowbie character to Pandaria or Draenor with the help of a portal and a two-seater flying mount, setting loot to Free For All, killing a bunch of mobs and having the lowbie loot them and vendor the trash and greens.

More information than you wanted most likely, but I thought I'd mention these things for anyone else that might run into this.