xkb remap Ctrl+j to be Ctrl+Page_Down [closed]

I already have an .xkb layout file with some stuff going on, basically altgr-intl with HJKL as arrow keys:

xkb_keymap {    xkb_keycodes  { include "evdev+aliases(qwerty)" };    xkb_types     { include "complete" };    xkb_compat    { include "complete" };    xkb_symbols   {        include "pc+us(altgr-intl)+inet(evdev)+altwin(swap_lalt_lwin)+capslock(swapescape)"        key <AC06> { [h, H, Left] };        key <AC07> { [j, J, Down] };        key <AC08> { [k, K, Up] };        key <AC09> { [l, L, Right] };    };    xkb_geometry  { include "pc(pc104)" };};

I want to remap Ctrl+j to Ctrl+Page_Down (and k/PgUp), but not modify any other Ctrl+* combinations.

I want to have Ctrl+Page_Down easily accessible for navigating tabs in browsers and editors.