Sending items from one picker to another

[maskudo]

I want to send files I have searched to live_grep for further processing.
In telescope, I used to do this:

			local send_find_files_to_live_grep = function()
				local files = {}
				local prompt_bufnr = vim.api.nvim_get_current_buf()
				require("telescope.actions.utils").map_entries(
					prompt_bufnr,
					function(entry, _, _)
						table.insert(files, entry[0] or entry[1])
					end
				)
				require("telescope.builtin").live_grep({
					search_dirs = files,
				})
			end

How do I do the same thing in Snacks.picker?
I'd imagine it would be something like this, but I cannot get it to work:

local switch_to_grep = function(picker, _)
	local snacks = require("snacks")
	local items = picker:items()
	snacks.picker.grep({
		hidden = true,
		items = items,
	})
	-- local files = {}
	-- for _, item in ipairs(items) do
	-- 	table.insert(files, item._path)
	-- end
	-- snacks.picker.grep({
	-- 	hidden = true,
	-- 	glob = files,
	-- })

end

Conversely, I also want to send the items I've grepped for to find_files for further matching.