The other possible solutions
Assumption: You are using some flavour of Linux.
1) create a symlink into the apach document root.
In the apache docuement root create a new sub folder : you may decide to call it something like blastData, you will obviously need to be be 'root' to do this.
Now you need to create a link to the 'actual' data directory, this is the tricky bit, you need to create it in the 'correct direction', so lets say that your parent directory is called blastServer, and is located in your home directory
ln -s ~\blastServer \path\To\Apache\Document\Root\blastData
You will need to make sure that the read/write permissions are correct, or the apache server won't be able to read the info and be able to display it to anyone.
you can have hard or soft links see this tutorial
2) create a number of 'virtual servers' within the apache config file.
This would require the creation of a separate user just for the blastServer (which will definately keep all the data well separated from everything else, and enable it to be easily migrated to another machine at a later point).
Then you must modify your apache config file to include this virtual server root location.
The reason reason this requires a linux desktop / server is that is what I use, and I've never set up apache on windows.
Also the availability of hard or soft links makes the possibility of accidentaly deleting the file(S) much less likely.