sharing xul elements between toolbars

hi, i am new to xul. i was wondering if there was a way to share elements between 2 toolbars.

for example, lets say i have toolbar_1 with a text box and a button. i want to create toolbar_2 with the same button as the button which i defined in toolbar_1 along with other buttons. i would also like to style the toolbar_1 and toolbar_2 differently. 

how can i achieve this? i am aware of the use of overlays but i hope to use a different method. 

is this possible using the DOM?

thank you