Use devilspie2, which can be installed via sudo qubes-dom0-update devilspie2
Then under ~/.config/devilspie2/ create ws.lua
In it write this:
qube = get_window_property("_QUBES_VMNAME");
ws = 0;
if qube == "personal" then ws = 1;
if qube == "work" then ws = 2;
if ws > 0 then
set_window_workspace(ws);
change_workspace(ws);
end