How to Restrict prop_search to specific types

I am trying to restrict the selection an user can make for a text object and a curve object

what can i do to restrict the choices for the prop_search commands? When the user clicks in the Text Object box, i want to show him just the text objects available, same with the path object box, just show path objects.

import bpy    

class FOLLOWINGLETTERS_Panel(bpy.types.Panel):
    """Creates a Panel in the Object properties window"""
    bl_label = "Following Letters Panel"
    bl_idname = "FOLLOWINGLETTERS_hello"
    bl_space_type = 'PROPERTIES'
    bl_region_type = 'WINDOW'
    bl_context = "object"
    # Add properties to all objects in Scene
    bpy.types.Scene.obj_property = bpy.props.FloatProperty(name = "TextThickness")

    def draw(self, context):
        layout = self.layout

        scene = context.scene    
        layout.prop_search(scene, "theTextObject", scene, "objects", text="Text Object", icon='OUTLINER_OB_FONT')
        TextObj = scene.objects[scene.theTextObject]
        layout.prop_search(scene, "thepathObject", scene, "objects", text="Path Object", icon='OUTLINER_OB_CURVE')
        PathObj = scene.objects[scene.thepathObject]