Pretty good sliders

Ingredients

• 1 2/3 lb ground sirloin, beef
• 1 tsp salt
• 1 1/2 tsp granulated garlic powder
• 1 tsp ground black pepper
• 12 oz bacon, sliced
• 8 oz mushrooms
• 1/4 cup margarine
• 3 tbsp mayonnaise
• 3 tsp Heinz ketchup
• 3 tsp yellow prepared mustard
• 2 small tomatoes
• 1/2 cup sliced onions
• 1 tsp Lawry's seasoned salt
• 3 slice pavolone cheese
• 3 slice swiss cheese
• 12 King's Hawaiian bread
• 3 large kosher pickles quartered