I have a hosting with 2 domains how do i redirect

[Dutch John]

I have a hosting with 2 domains how do i redirect to a subdirectory
domain 1 is my hosting domain domain2 is an alias

e.g
domain1.info/somedir/somefile redirectes to domain1.info/DOMAIN1DIR/somedir/somefile
and
domain2.info/somedir/somefile redirectes to domain2.info/DOMAIN2DIR/somedir/somefile

I looked thru this forum and tried some solutions but either i see the hosting domain in de URL or is is very slow

Kind Regards John