主催の「災害」会議実行委員会も、当プロジェクトと同様に、災害をきっかけに発足したコミュニティとのこと。
The とのこと at the end means "They say~~" "I hear~~".
It has its own entry in this J-E dictionary:
とのこと; との事; I'm told; I'm passing on a message; he was informed; indicates that one has heard the preceding information from somebody
and in デジタル大辞泉:
人から聞いた話であることを表す。…という。…だそう。「彼は会社をやめたとのことだ」
You can rephrase it as 「とのこと だ/です」, 「ということ だ/です」, 「なのだそう だ/です」, 「という話 だ/です」 etc. depending on the situation/formality. To my ear, ending a sentence with 「~とのこと」 sounds more literary than 「~とのことです」「~ということです」 etc.
災害をきっかけに発足したコミュニティ is a noun phrase, the relative clause 災害をきっかけに発足した modifying the コミュニティ, as the other poster said.
So I think your sentence means something along the lines of:
The host "Disaster" Conference Executive Committee, as well as our project, is a community launched in the wake of a disaster, they said.
or
They say that the Executive Committee of the Conference on "Disaster", which hosted/sponsored this event, was launched because of a disaster, just like our project was.
Hope my English makes sense.