I'm not totally sure if IPTV can include EPG, I have always seen IPTV EPG referred to as an external source, but I could be wrong.
Based on the other posts that you have made to the forum, are you trying to get the EPG from your remove TVH Raspberry Pi onto your local TVH?
If so, TVH can both consume and produce an XMLTV feed.
https://docs.tvheadend.org/documentation/development/json-api/other-functions
$ curl http://192.168.0.1:9981/xmltv/channelid/<channelid>
$ curl http://192.168.0.1:9981/xmltv/channelnumber/<channelnumber>
$ curl http://192.168.0.1:9981/xmltv/channelname/<channelname>
$ curl http://192.168.0.1:9981/xmltv/channel/<channelUUID>
$ curl http://192.168.0.1:9981/xmltv/tagid/<tagid>
$ curl http://192.168.0.1:9981/xmltv/tagname/<tagname>
$ curl http://192.168.0.1:9981/xmltv/tag/<tagUUID>
You would need to write a script on your local TVH server to extract the XMLTV data from your remote TVH server and feed that into your local TVH instance. You would need to enable the XMLTV EPG grabber module and possible associate each 'EPG Grabber Channel' with the IPTV channel that you have defined.
Because you mentioned geoblocking
on a previous post, this information is provided with the understanding that you are trying to access services to which you are legally entitled to access.