Multiple contact XML field updates SQL 2008 R2

Question

Hi, I'm not sure of the soundness of the following architecture, but right now, the following information is for a prototype at this time.

I have a stored procedure that currently lets me:

1. Pass an owner memberID and say an ID for a new event record
2. In the member table, I have an XML field say called events, and the new event ID gets added as a new node to that XML field

All works fine, and it then makes it easy to retrieve the event ID's for that member (actually it does a join to the actual event table, and retrieves the req. data).

I now need to:

a) Instead of passing just the owner member ID, need to pass say a collection of member ID's to add that new event ID to..

The other option of course is to get the member ID's separately, and loop through within say c# code and call the proc x times.. doesn't seem a good idea...

Any thoughts? I have included the existing proc below which deals with an individual member ID.

CREATE PROCEDURE [dbo].[put_addEventIDmemberXML]
    @memberID           bigint = null,
    @addNodeID          varchar(255) = null
AS
BEGIN
    SET NOCOUNT ON;

    /*  Get our XML nodes for the owner ID  */
    DECLARE @x XML
    DECLARE @newIDnodeXML XML
    SET @newIDnodeXML = '<id>' + @addNodeID + '</id>' 
    set @x = (select memberEvents from members where memberID = @memberID)

    /*  Check if the new node ID exists within our member XML nodes */
    IF NOT EXISTS (
        SELECT * FROM @x.nodes('/root/id') n(x) WHERE x.value('.','bigint') = @addNodeID
    ) 
    begin
        SET @x.modify('insert sql:variable("@newIDnodeXML") as last into /root[1]')
        UPDATE dbo.members
        SET memberEvents = @x
        WHERE memberID = @memberID
    end
END