relay triggering another relay

Hi, i installed a set of aftermarket horns to replace my one wimpy horn but with the stock relay they still arent that loud. i tried putting a different relay in place of stock but still the same. i tried using the stock relay to trigger the relay horns came with and it was MUCH louder.    My question is , is it safe/ok to have the stock relay trigger a second relay triggering the horns? Thanks :)

its on a 1996 nissan altima

Mount the trumpets inside the splash shield facing the road (down) installing them in the engine bay is a waste of time because the engine parts and installation muffle the sound. Also I'd use the original relay and if necessary upgrade the fuse, that's what I do and I've owned two Maximas and right now a smaller Nissan all with air horns. If you piggy-back the second relay, (use the NEG horn push wire to trigger it), and you press the horn for a second or less,you get the original horns, hold the horn button longer for the air horns. Without the second relay it's instant.

Keeping in mind the usual (traditional) "hot" relay with grounded horn-switch (ie, a 3-terminal relay, else "normal" with #30 & #86 connected together to +12V). (I presume it's wired traditionally.) I'd probably run a new fuse and heavier +12V power cable for the new horn(s), but that assumes it uses 4-terminal relay IF the horns only work with IGN (or ACC) on - ie, #86 of the new relay to "B" or +12V supply of the original relay, then #85 to the horn-switch (usually "S" on a 3-terminal horn relay) - unless you want the new horns to be usable at any time (then a 3-terminal horn relay or #86 to #30 as normal).