I opened Web interface and I added my provider's xmltv.php link but I have no idea how to merge another EPG link into this one.
I need http://reddeviliptv.com/epg.xml but xTeve won't let me add it.
I actually even need 3rd EPG source since both my provider and Reddevil EPG don't have Italian Sky Sport EPG.
I know about Kodi IPTV Merge and I am using it but TiViMate accept only 2 sources, I need 3.
You don't really merge EPGs with xTeVe. You load them separately and then you use the mapping function to assign which epg you want to use for which channel. It's a channel by channel mapping.
xTeVe won't load the epg you listed because that particular one is not formatted correctly. I wasn't able to load it either.