Pan domain name resolution, how to let sub-domain name binding subdirectories

Pan domain name resolution, how to make sub-domain name binding subdirectories?
Domain name a.com pan domain name resolution to IP 8.8.8.8
Host binding domain name a.com
Then the first page lists the level two domain name hope

1.a.com binding/WWWROOT/1
2.a.com binding/WWWROOT/2
3.a.com binding/WWWROOT/3
4.a.com binding/WWWROOT/4
5.a.com binding/WWWROOT/5

Do not manually bind, randomly generated two-level domain name binding to the corresponding level two directory
How do you do this, with pseudo-static or what?
------Solution--------------------
#让1. A.com Accessing the/WWWROOT/1 directory
Rewritecond%{http_host} ^1.a.com$ [NC]
Rewritecond%{request_uri}!^/wwwroot/1/
Rewriterule ^ (. *) $/wwwroot/1/$1
Rewritecond%{http_host} ^1.a.com$
Rewriterule ^ (/)? $/wwwroot/1/index.html [L]

