LJCC and JW3 are not the only groups who have made a move towards merger. For more than a year the Board of Deputies and the Jewish Leadership Council have been talking about joining forces - although the preferred word is "unification".
This week's announcement of a closer alliance between the Reform and the Liberal movements has been on the cards for a while. The two movements explored merger in the 1980s, but are unlikely to go as far as that this time.
A merger between the two biggest social services, Jewish Care and Norwood (both of which have absorbed other organisations themselves) has also been mooted from time to time.
JNF UK even once considered getting together with the UJIA to form one central Israel organisation, but the different outlooks of their leaders would make that seem far-fetched now.
To some, it would make sense to unite the different friends of Israeli universities - Hebrew U, Tel Aviv etc - into a single agency. Ditto for the friends group of Israeli hospitals. But organisations are jealous of their individual identities and they believe they can raise more on their own rather than being part of a broader group.
One option short of full merger is for different charities to share administrative functions to cut costs: the Pears Foundation-funded JHub provides shared office space for a number of smaller outfits - a model others could follow.
It has even been suggested that groups such as Bicom, the Zionist Federation and the political Friends of Israel groups should unite to create a one-stop Israel lobby, similar to the American Aipac.