LinqToSql query to filter objects by string which contain any from list of another strings

by linqToSql i want to return objects which have in theirs xml property ActivityId, one of ID from another collection which stores same kind of objects which i want to return. If i dont have collection to compare but single object i use for example something like this:

string activity = String.Format("name=\"activityId\" value=\"{0}\"", value);
            var activities = DbContext.Activities.Where(x => x.XmlData.ToString().Contains(activity)

And thats works, but now i need to put as variable "activity" list of strings not single string and that became problem. So for bether explain ill give more info:

I have such data ( pseudo code ):

Class Activity{
   int Id;
   byte Type;
   XElement XmlData;
}

"Type" property in this class means kind of activity which was made. in "XmlData" property i'm storing data like that:

<data>
  <property name="activityId" value="10" />
  <property name="commentId" value="1" />
</data>

in another query ( lets name it "Query1", i've got collections of activities, for example Activities.ID = 1,2,3,4,5

now i want to get collection of Activities which will contain in XmlData "activityId", id from Query1.

something simmilar of that what i want to get is:

var activities = new List<string>();
            pictureActivities.ToList().ForEach(x=> activities.Add(String.Format("name=\"activityId\" value=\"{0}\"", x.Id)));
            var commentActivities = DbContext.Activities.Where(x => x.Type == 18 && x.XmlData.ToString().Contains(activities.Any()));

I hope you understand what im trying to achieve. Thanks for help.