Directory ⁄var⁄www⁄hosts⁄web1 / is not writable AND Security-Enhanced_Linux

I have been trying to solve this problem for several weeks but cannot find a solution. I would like to host several websites (vhosts) but have always the same problem: the CMS (z.B. Joomla, Typo3…) cannot access the directory "/var/www/vhosts/web1“. From the link below I have read that SELinux interrupts the directory, but I do not understand how I could set the approvals for a FTP user to „user_webmaster“ or how I could release specific folders (for example "/var/www/gosts/web1/tmp"). I do not want to grant a general access that sets the approvals to 0777.