I understand. I used to split the family trees of my mother and father, to accomodate posting them to a website that did not allow large files. Then I ran into a problem. Some of their relatives had intermarried. This made splitting them very difficult.
Fortunately I found another web host that supports large files, so I can have PAF generate the web pages, including indexes, from my main file without needing to split it. This web host is presently free (I can only hope it remains that way. But if they start charging a reasonable amount I would pay for the convenience.)
On my web site, the Surname Index and to the Name Index link directly to the web pages generated by PAF. I use the free Kompozer software to create and edit the additional web pages. It is simple to use, with no need to learn HTML code unless you want to.