add a clan alliance bank, how it works is whatever clanA put an item in, only clans that clanA is allied towards may see the items in the clan alliance bank, and perms will work the same as the clan banks do where each clan can select who can pull out of the alliance bank

example of it not working:
Clan A allied to Clan B NOT C
Clan B allied to Clan A and Clan C
Clan C allied to Clan B NOT A

Clan A items cannot be seen by clan C but Clan B can see both ClanA and clanC items
Clan A can only see Clan B items and Clan C can only see Clan B Items