How to customize less command

[dev.mighty]

I have vey large log files on remote servers to view(not to edit), if I open them in vi/vim/emacs it takes huge time and sometimes hangs. Less is more comfortable, but I want it to be customized as follows. When I search for a word it gets highlighted in black,
1)can I change the color?
when I search for other word the previous search highlights gets cleared and the new word gets highlighted(if found).
2)Can I keep the old search word highlighted while highlighting new search word in a different color?
3)I have XML in logs files can I fold and unfold those XML tags in less.

Please advise me or give some references to go through (I googled a lot but couldn’t find).